4-Way 2-Position Directional Valve (2P)

R2026b

4-Way 2-Position Directional Valve in the two-phase fluid domain

Since R2024b

Libraries:
Simscape / Fluids / Two-Phase Fluid / Valves & Orifices / Directional Control Valves

Description

The 4-Way 2-Position Directional Valve (2P) models a valve with four openings — such as the valves between an actuator, pump, and tank — in a two-phase fluid network. A single spool controls the valve operation according to the signal at port S. You can set the baseline configuration of your valve by specifying the orifices that are open when the spool moves in the positive direction and negative directions in the Positive spool position open connections and Negative spool position open connections parameters, respectively. You can set the valve opening model in the Orifice parameterization parameter as a linear relationship or function of user-provided data, which you can apply to one or all flow paths in the valve.

This block is a composite component that comprises of multiple instances of the Orifice (2P) block. Refer to the Orifice (2P) block for more details about valve parameterizations and block calculations. In some configurations, this valve resembles a 3-way valve. To set additional flow paths when the spool is in the neutral position, see the 4-Way 3-Position Directional Valve (2P) block.

This image shows an example valve setup where the valve is connected to a tank, actuator, and pump and the Positive spool position open connections parameter is P-B, A-T:

This image shows the valve when the Negative spool position open connections parameter is P-A, B-T:

In this configuration, when the signal at port S moves the spool to a negative position, the paths between ports P and A and between ports B and T are open to flow. The paths between ports P and B and ports A and T are closed to flow.

This image shows the valve when the Positive spool position open connections parameter is P-B, A-T:

In this configuration, when the signal at port S moves the spool to a positive position, the paths between ports P and B and between ports A and T are open to flow and the paths between ports P and A and between ports B and T are closed.

The schematic that represents this configuration is:

Hydraulic schematic symbol for a 4-way 2-position directional valve with ports A, B, P, and T

The left-hand side corresponds to the positive position and the right-hand side corresponds to the negative position. The valve transitions through positions in the neutral mid-section.

Spool Displacement and Valve Configuration

The spool stroke is the amount of spool travel an orifice takes to fully open from a closed position. You can use the Orifice parameterization and Area characteristics parameters to specify the flow path characteristics:

Orifice Parameterization	Identical for All Flow Paths	Different for Each Flow Path
`Linear - Area vs. spool travel`	The Spool travel between closed and open orifice parameter defines the spool stroke	The Spool travel between closed and open orifice parameter defines the spool stroke for each orifice
`Tabulated data - Area vs. spool travel`	The difference between the first and last element of the Spool travel vector parameter defines the spool stroke	The difference between the first and last element of the Spool travel vector parameter for each orifice
`Tabulated data - Volumetric flow rate vs. spool travel and pressure drop`or `Tabulated data - Mass flow rate vs. spool travel and pressure drop`	The difference between the first and last element of the Spool travel vector, ds parameter defines the spool stroke	The difference between the first and last element of the Spool travel vector, ds parameter defines the spool stroke for each orifice

The direction of the spool movement depends on the spool stroke, orifice orientation, and signal at port S. This table shows the spool travel for an orifice depending on the selections for the Positive spool position open connection and Negative spool position open connection parameters:

Spool Position When Orifice Is Open	Spool Travel, ΔS
Orifice always closed: orifice not selected for the Positive spool position open connection or Negative spool position open connection parameters	N/A
Orifice always open: orifice selected for both the Positive spool position open connection and Negative spool position open connection parameters	N/A
Negative: orifice selected for only Negative spool position open connection parameter	S_{orifice_max} + spool stroke – S
Positive: orifice selected for only Positive spool position open connection parameter	S_{orifice_max} – spool stroke + S

Where S_{orifice_max} is the spool position at the maximum orifice area defined for each orifice. The orifice area saturates at the leakage area when ΔS is negative and saturates at the maximum orifice area when the orifice is fully open. When the orifice is fully open, ΔS is equal to the spool stroke, so ΔS greater than the spool stroke does not further increase the orifice area.

This table shows the possible configurations of the 4-Way 2-Position Directional Valve (TL):

Configuration	Parameter Values
All four paths are closed during transition.	Positive spool position open connections: `P-A, B-T` Negative spool position open connections: `P-B, A-T` Spool position at maximum P-A orifice area > P-A spool stroke Spool position at maximum P-B orifice area < –P-B spool stroke Spool position at maximum A-T orifice area < –A-T spool stroke Spool position at maximum B-T orifice area > B-T spool stroke
All four paths are open during transition.	Positive spool position open connections: `P-A, B-T` Negative spool position open connections: `P-B, A-T` Spool position at maximum P-A orifice area < P-A spool stroke Spool position at maximum P-B orifice area > –P-B spool stroke Spool position at maximum A-T orifice area > –A-T spool stroke Spool position at maximum B-T orifice area < B-T spool stroke
A-T and B-T are closed during transition.	Positive spool position open connections: `P-A, B-T` Negative spool position open connections: `P-B, A-T` Spool position at maximum P-A orifice area < P-A spool stroke Spool position at maximum P-B orifice area > –P-B spool stroke Spool position at maximum A-T orifice area < –A-T spool stroke Spool position at maximum B-T orifice area > B-T spool stroke
P-A and P-B are closed during transition.	Positive spool position open connections: `P-A` Negative spool position open connections: `P-B` Spool position at maximum P-A orifice area > P-A spool stroke Spool position at maximum P-B orifice area < –P-B spool stroke
P-B and B-T are closed during transition.	Positive spool position open connections: `P-B, A-T` Negative spool position open connections: `P-A, B-T` Spool position at maximum P-A orifice area < P-A spool stroke Spool position at maximum P-B orifice area > P-B spool stroke Spool position at maximum A-T orifice area > A-T spool stroke Spool position at maximum B-T orifice area < –B-T spool stroke
P-A and A-T are closed during transition.	Positive spool position open connections: `P-B, A-T` Negative spool position open connections: `P-A, B-T` Spool position at maximum P-A orifice area < –P-A spool stroke Spool position at maximum P-B orifice area < P-B spool stroke Spool position at maximum A-T orifice area > A-T spool stroke Spool position at maximum B-T orifice area > –B-T spool stroke
P-A, P-B, and B-T are open during transition.	Positive spool position open connections: `P-A, P-B` Negative spool position open connections: `P-A, B-T` Spool position at maximum P-A orifice area < P-A spool stroke Spool position at maximum P-B orifice area < P-B spool stroke Spool position at maximum A-T orifice area = any value Spool position at maximum B-T orifice area > –B-T spool stroke
P-A, A-T, and B-T are open during transition.	Positive spool position open connections: `P-B, A-T` Negative spool position open connections: `P-A, P-B` Spool position at maximum P-A orifice area > –P-A spool stroke Spool position at maximum A-T orifice area < A-T spool stroke Spool position at maximum B-T orifice area = any value
P-A and P-B are closed during transition. A-T is always closed.	Positive spool position open connections: `P-A, P-B` Negative spool position open connections: `P-A, B-T` Spool position at maximum P-B orifice area > P-B spool stroke Spool position at maximum B-T orifice area < –B-T spool stroke
All paths are closed during transition.	Positive spool position open connections: `P-B, A-T` Negative spool position open connections: `P-A, P-B` Spool position at maximum P-A orifice area < –P-A spool stroke Spool position at maximum P-B orifice area > P-B spool stroke Spool position at maximum A-T orifice area > A-T spool stroke
A-T is open during transition. P-A is closed during transition.	Positive spool position open connections: `P-A, P-B` Negative spool position open connections: `P-A, B-T` Spool position at maximum P-A orifice area > P-A spool stroke Spool position at maximum P-B orifice area > P-B spool stroke Spool position at maximum A-T orifice area = any value Spool position at maximum B-T orifice area > –B-T spool stroke
B-T is open during transition. P-B is closed during transition.	Positive spool position open connections: `P-B, A-T` Negative spool position open connections: `P-A, P-B` Spool position at maximum P-A orifice area < –P-A spool stroke Spool position at maximum P-B orifice area > P-B spool stroke Spool position at maximum A-T orifice area < A-T spool stroke Spool position at maximum B-T orifice area = any value
P-A is closed during transition.	Positive spool position open connections: `P-A, B-T` Negative spool position open connections: `P-A, P-B` Spool position at maximum P-A orifice area > P-A spool stroke Spool position at maximum P-B orifice area < –P-B spool stroke Spool position at maximum B-T orifice area > B-T spool stroke
P-B is closed during transition.	Positive spool position open connections: `P-A, P-B` Negative spool position open connections: `P-B, A-T` Spool position at maximum P-A orifice area > P-A spool stroke Spool position at maximum P-B orifice area > P-B spool stroke Spool position at maximum A-T orifice area > –A-T spool stroke

Valve Orifice Parameterizations

The Modeling option parameter controls the parameterization options for a valve designed for modeling either vapor or liquid, but does not impact the fluid properties. The block calculates fluid properties inside the valve from inlet conditions.

The Orifice parameterization parameter specifies the model for the open area or flow rate through one or all of the valve orifices. If you set Area characteristics to Identical for all flow paths, the block applies the same data for all flow paths. When you select Different for all flow paths, the block uses individual parameterizations for each flow path.

Liquid Valve Parameterization

When Modeling option is Liquid operating condition, the block parameterizations are designed for a valve controlling liquid flow.

When Orifice parameterization is Linear - Area vs. spool travel, the opening area is a linear function of the spool position received as a signal at port S

$A_{o r i f i c e} = \frac{(A_{\max} - A_{l e a k})}{Δ S_{\max}} Δ S + A_{l e a k},$

where:

ΔS is the spool travel.
A_orifice saturates at A_leak when ΔS is negative and saturates at A_max when the orifice is fully open. When the orifice is fully open, ΔS is equal to the spool stroke, so a value of ΔS that is greater than the spool stroke does not increase the orifice area.
ΔS_max is the value of the Spool travel between closed and open orifice parameter.
A_max is the value of the Maximum orifice area parameter.
A_leak is the value of the Leakage area parameter.

When the valve is in a near-open or near-closed position in the linear parameterization, you can maintain numerical robustness in your simulation by adjusting the Smoothing factor parameter. If the Smoothing factor parameter is nonzero, the block smoothly saturates the opening area between A_leak and A_max. For more information, see Numerical Smoothing.

When Orifice parameterization is Tabulated data - Area vs. spool travel, you can provide spool travel vectors for your system or for individual flow paths between ports P, A, B, and T. The block uses this data to calculate the relationship between the orifice area and spool displacement. The block uses interpolation to determine the opening area between given data points. A_leak and A_max are the first and last parameters of the opening area vector, respectively.

When Orifice parameterization is Tabulated data - Nominal mass flow rate vs. spool travel, the block calculates the mass flow rate for each orifice from the nominal conditions you specify in the block parameters. The spool position signal from port S scales the orifice opening area, which can also scale mass flow rate.

Vapor Valve Parameterization

When Modeling option is Vapor operating condition, the block parameterizations are designed to model a valve that controls vapor flow.

The method the block uses to control each orifice depends on the Opening characteristic parameter:

Linear — The measure of flow capacity depends on the spool position at port S. As the spool displaces to open to orifice, the measure of flow capacity scales from the specified minimum to the specified maximum.
Tabulated — The block calculates the measure of flow capacity as a function of the spool position at port S. This function uses a one-dimensional lookup table.

The Orifice parameterization parameter determines how the block calculates the flow rate in each orifice:

Cv flow coefficient — The flow coefficient C_v scales the flow rate in each orifice. The flow coefficient measures the ease with which a fluid can flow when driven by a certain pressure differential.
Kv flow coefficient — The flow coefficient K_v, where $K_{v} = 0.865 C_{v}$ , scales the flow rate in each orifice. The flow coefficient measures the ease with which a fluid can flow when driven by a certain pressure differential.
Orifice area — The size of the orifice area scales the flow rate in each orifice.

Visualize Orifice Openings

To generate a characteristic plot of the valve, click the Plot button next to Valve characteristics. The plot shows the orifices specified by the parameters in Valve Configuration section. When you set the parameters in the Valve Configuration tab to the same orifice, the orifice opening is a constant.

Click Reload Data to update the data in the figure.

This image shows the default configuration for the block:

Positive spool position open connections is P-A, B-T
Negative spool position open connections is P-B, A-T

All other spool positions are at the default values.

Assumptions and Limitations

There is no heat exchange between the valve and the environment.
When Modeling option is Liquid operating condition, the results may not be accurate outside of the subcooled liquid region. When Modeling option is Vapor operating condition, the results may not be accurate outside of the superheated vapor region. To model a valve in a liquid-vapor mixture, set Modeling option to Liquid operating condition.

Ports

Conserving

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A — Entry or exit port
two-phase fluid

Two-phase fluid conserving port associated with the entry or exit port to the valve.

Programmatic Use

Port: A

B — Entry or exit port
two-phase fluid

Two-phase fluid conserving port associated with the entry or exit port to the valve.

Programmatic Use

Port: B

P — Entry or exit port
two-phase fluid

Two-phase fluid conserving port associated with the entry or exit port to the valve.

Programmatic Use

Port: P

T — Entry or exit port
two-phase fluid

Two-phase fluid conserving port associated with the entry or exit port to the valve.

Programmatic Use

Port: T

Input

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S — Spool displacement, m
physical signal

Physical signal associated with the spool displacement, in m.

Programmatic Use

Port: S

Parameters

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Modeling option — Modeling option for fluid phase
`Liquid operating condition` (default) | `Vapor operating condition`

Modeling option for the fluid phase at the valve. Set this parameter to Liquid operating condition if the two-phase fluid at the block location is in a liquid state. Set this parameter to Vapor operating condition if the two-phase fluid at the block location is in a vapor state.

Programmatic Use

Parameter:	`ComponentPath`
Values:	`"fluids.two_phase_fluid.valves_orifices.directional_control_valves.directional_valve_4_way_2_position_liquid"` \| `"fluids.two_phase_fluid.valves_orifices.directional_control_valves.directional_valve_4_way_2_position_vapor"`

Valve Configuration

Positive spool position open connections — Flow paths open when spool is in positive position
`P-A, B-T` (default) | `P-A, P-B` | `P-B, A-T` | `P-A` | `P-B` | `P-A, P-B, A-T, B-T`

Flow paths open when the spool is in a positive position. This parameter sets the valve configuration and defines the direction of spool movement according to the signal received at port S.

Programmatic Use

Parameter: open_orifices_pos

Values: "fluids.two_phase_fluid.valves_orifices.directional_control_valves.enum.OpenOrifices4Way2Position.PA_BT" | "fluids.two_phase_fluid.valves_orifices.directional_control_valves.enum.OpenOrifices4Way2Position.PA_PB" | "fluids.two_phase_fluid.valves_orifices.directional_control_valves.enum.OpenOrifices4Way2Position.PB_AT" | "fluids.two_phase_fluid.valves_orifices.directional_control_valves.enum.OpenOrifices4Way2Position.PA" | "fluids.two_phase_fluid.valves_orifices.directional_control_valves.enum.OpenOrifices4Way2Position.PB" | "fluids.two_phase_fluid.valves_orifices.directional_control_valves.enum.OpenOrifices4Way2Position.PA_PB_AT_BT" | "fluids.two_phase_fluid.valves_orifices.directional_control_valves.enum.OpenOrifices4Way2Position.AllClosed"

Negative spool position open connections — Flow paths open when spool moves in negative direction
`P-B, A-T` (default) | `P-A, B-T` | `P-A, P-B` | `P-A` | `P-B` | `P-A, P-B, A-T, B-T`

Flow paths open when the spool moves in the negative direction. This parameter sets the valve configuration and defines the direction of spool movement according to the signal received at port S.

Programmatic Use

Parameter: open_orifices_neg

Values: "fluids.two_phase_fluid.valves_orifices.directional_control_valves.enum.OpenOrifices4Way2Position.PB_AT" | "fluids.two_phase_fluid.valves_orifices.directional_control_valves.enum.OpenOrifices4Way2Position.PA_BT" | "fluids.two_phase_fluid.valves_orifices.directional_control_valves.enum.OpenOrifices4Way2Position.PA_PB" | "fluids.two_phase_fluid.valves_orifices.directional_control_valves.enum.OpenOrifices4Way2Position.PA" | "fluids.two_phase_fluid.valves_orifices.directional_control_valves.enum.OpenOrifices4Way2Position.PB" | "fluids.two_phase_fluid.valves_orifices.directional_control_valves.enum.OpenOrifices4Way2Position.PA_PB_AT_BT" | "fluids.two_phase_fluid.valves_orifices.directional_control_valves.enum.OpenOrifices4Way2Position.AllClosed"

Model Parameterization

Area characteristics — Flow equations for orifices
`Identical for all flow paths` (default) | `Different for each flow path`

Whether to apply uniform or individual flow equations for the valve orifice area. When you set this parameter to Identical for all flow paths, the block uses the same orifice and spool geometries, flow rates, pressure, and area vectors for all valve orifices. When you set this parameter to Different for each flow path, you can specify these parameters individually for each orifice. For both settings, orifices A, B, P, and T have the same cross-sectional areas, discharge coefficients, and Reynolds numbers when you set Orifice parameterization to Linear - Area vs. spool travel or Tabulated data - Area vs. spool travel.

Programmatic Use

Parameter:	`area_spec`
Values:	`"fluids.two_phase_fluid.valves_orifices.directional_control_valves.enum.AreaSpec.Identical"` \| `"fluids.two_phase_fluid.valves_orifices.directional_control_valves.enum.AreaSpec.Different"`

Orifice parameterization — Variable or constant orifice parameterization
`Linear - Area vs. spool travel` (default) | `Linear - Nominal mass flow rate vs. spool travel` | `Tabulated data - Area vs. spool travel` | `Cv flow coefficient` | `Kv flow coefficient` | `Orifice area`

Method the block uses to calculate the mass flow rate from the pressure difference across the orifice or the pressure difference from the mass flow rate.

When Modeling option is Liquid operating condition, the choices for this parameter are:

Linear - Area vs. spool travel
Linear - Nominal mass flow rate vs. spool travel
Tabulated data - Area vs. spool travel

When Modeling option is Vapor operating condition, the choices for this parameter are:

Cv flow coefficient
Kv flow coefficient
Orifice area

Programmatic Use

Parameter:	`liquid_valve_parameterization`
Values:	`"fluids.two_phase_fluid.valves_orifices.directional_control_valves.enum.LiquidOrificeParameterization.LinearArea"` \| `"fluids.two_phase_fluid.valves_orifices.directional_control_valves.enum.LiquidOrificeParameterization.LinearNominalMassFlow"` \| `"fluids.two_phase_fluid.valves_orifices.directional_control_valves.enum.LiquidOrificeParameterization.Tabulated1DArea"`

Parameter:	`vapor_valve_parameterization`
Values:	`"fluids.two_phase_fluid.valves_orifices.enum.VaporOrificeParameterization.Cv"` \| `"fluids.two_phase_fluid.valves_orifices.enum.VaporOrificeParameterization.Kv"` \| `"fluids.two_phase_fluid.valves_orifices.enum.VaporOrificeParameterization.Area"`

Spool travel between closed and open orifice — Maximum spool stroke
`0.005 m` (default) | positive scalar

Maximum distance of spool travel.

Dependencies

To enable this parameter, set Area characteristics to Identical for all flow paths and either:

Modeling option to Liquid operating condition and Orifice parameterization to Linear - Area vs. spool travel.
Modeling option to Vapor operating condition and Opening characteristic to Linear.

Programmatic Use

Parameter: del_S_max

Maximum orifice area — Maximum orifice opening area
`1e-4 m^2` (default) | positive scalar

Largest open area of each orifice during the operation of the valve.

Dependencies

To enable this parameter, set Area characteristics to Identical for all flow paths and either:

Modeling option to Liquid operating condition and Orifice parameterization to Linear - Area vs. spool travel.
Modeling option to Vapor operating condition, Orifice parameterization to Orifice area, and Opening characteristic to Linear.

Programmatic Use

Parameter: orifice_area_max

Parameter: valve_area_max

Nominal mass flow rate at maximum orifice opening — Rated mass flow rate
`0.1` kg/s (default) | positive scalar

Typical, rated, or design mass flow rate at the orifice maximum opening position.

Dependencies

To enable this parameter, set Modeling option to Liquid operating condition, Area characteristics to Identical for all flow paths, and Orifice parameterization to Linear - Nominal mass flow rate vs. spool travel.

Programmatic Use

Parameter: mdot_nominal_max

Nominal pressure drop at maximum orifice opening — Rated pressure drop
`0.001` MPa (default) | positive scalar

Typical, rated, or design pressure drop at the orifice maximum opening position.

Dependencies

Programmatic Use

Parameter: delta_p_nominal_max

Nominal inlet condition specification — Method of determining inlet fluid state
`Temperature` (default) | `Vapor quality` | `Vapor void fraction` | `Specific enthalpy` | `Specific internal energy`

Method of determining the inlet fluid state. The block determines the orifice nominal inlet specific volume from the tabulated fluid properties data based on the value of the Nominal inlet pressure and Nominal inlet condition specification parameters.

Dependencies

Programmatic Use

Parameter:	`energy_spec`
Values:	`"foundation.enum.energy_spec.temperature"` \| `"foundation.enum.energy_spec.quality"` \| `"foundation.enum.energy_spec.void_fraction"` \| `"foundation.enum.energy_spec.enthalpy"` \| `"foundation.enum.energy_spec.internal_energy"`

Nominal inlet pressure — Inlet fluid pressure
`0.101325` MPa (default) | positive scalar

Inlet pressure in nominal conditions. The block determines the inlet specific volume from the tabulated fluid properties data based on the value of the Nominal inlet pressure and Nominal inlet condition specification parameters.

Dependencies

Programmatic Use

Parameter: p_inlet

Nominal inlet temperature — Fluid temperature
`293.15` K (default) | positive scalar

Inlet fluid temperature in nominal operating conditions.

Dependencies

To enable this parameter, set Modeling option to Liquid operating condition, Area characteristics to Identical for all flow paths, Orifice parameterization to Linear - Nominal mass flow rate vs. spool travel, and Nominal inlet condition specification to Temperature.

Programmatic Use

Parameter: T_inlet

Nominal inlet vapor quality — Inlet vapor quality mass fraction
`0` (default) | positive scalar in the range [0,1]

Inlet mixture vapor quality by mass fraction in nominal operating conditions. A value of 0 means that the inlet fluid is subcooled liquid. A value of 1 means that the inlet fluid is superheated vapor.

Dependencies

Programmatic Use

Parameter: x_inlet

Nominal inlet vapor void fraction — Inlet volume fraction
`0` (default) | positive scalar in the range [0,1]

Inlet mixture volume fraction in nominal operating conditions. A value of 0 means that the inlet fluid is subcooled liquid. A value of 1 means that the inlet fluid is superheated vapor.

Dependencies

Programmatic Use

Parameter: alpha_inlet

Nominal inlet specific enthalpy — Inlet fluid specific enthalpy
`400` kJ/kg (default) | positive scalar

Inlet specific enthalpy in nominal operating conditions.

Dependencies

Programmatic Use

Parameter: h_inlet

Nominal inlet specific internal energy — Inlet specific internal energy
`400` kJ/kg (default) | positive scalar

Inlet specific internal energy in nominal operating conditions.

Dependencies

Programmatic Use

Parameter: u_inlet

Opening characteristic — Method to convert control signal to measure of flow capacity
`Linear` (default) | `Tabulated`

Method by which to convert the control signal specified at port S to the chosen measure of flow capacity.

Dependencies

To enable this parameter, set Modeling option to Vapor operating condition.

Programmatic Use

Parameter:	`opening_characteristic`
Values:	`"fluids.two_phase_fluid.valves_orifices.enum.OpeningCharacteristics.Linear"` \| `"fluids.two_phase_fluid.valves_orifices.enum.OpeningCharacteristics.Tabulated"`

Spool travel vector — Vector of spool opening distances relative to fully closed position
`[0, .00125, .0025, .00375, .005] m` (default) | 1-by-n vector

Vector of spool travel distances when parameterizing the orifice according to the tabulated valve area data. The vector elements must correspond one-to-one with the elements in the Orifice area vector parameter. List the values in ascending order. The first element must be 0. The block uses linear interpolation between table data points.

Dependencies

To enable this parameter, set Area characteristics to Identical for all flow paths and either:

Modeling option to Liquid operating condition and Orifice parameterization to Tabulated data - Area vs. spool travel.
Modeling option to Vapor operating condition and Opening characteristic to Tabulated.

Programmatic Use

Parameter: del_S_Cv_TLU

Parameter: del_S_Kv_TLU

Parameter: del_S_orifice_area_TLU

Parameter: del_S_TLU

Orifice area vector — Vector of valve opening areas
`[1e-10, 1e-05, 4e-05, 6e-05, .0001] m^2` (default) | 1-by-n vector

Vector of opening areas when parameterizing the orifice according to the tabulated valve area data. The vector elements must correspond one-to-one with the elements in the Spool travel vector parameter. List the values in ascending order. The elements must be greater than 0. The first element of this vector is the leakage area.

Dependencies

To enable this parameter, set Area characteristics to Identical for all flow paths and either:

Modeling option to Liquid operating condition and Orifice parameterization to Tabulated data - Area vs. spool travel.
Modeling option to Vapor operating condition, Orifice parameterization to Orifice area, and Opening characteristic to Tabulated.

Programmatic Use

Parameter: orifice_area_TLU

Parameter: valve_area_TLU

Maximum Cv flow coefficient — C_v coefficient that corresponds to maximally open component
`4` (default) | positive scalar

Value of the C_v flow coefficient when the orifice is fully open and the area available for flow is at a maximum. This parameter measures the ease with which the vapor traverses the resistive element when driven by a pressure differential.

Dependencies

To enable this parameter, set Modeling option to Vapor operating condition, Area characteristics to Identical for all flow paths, Orifice parameterization to Cv flow coefficient, and Opening characteristic to Linear.

Programmatic Use

Parameter: Cv_max

Cv flow coefficient vector — C_v coefficients for values in member position vector
`[1e-06, .8, 1.6, 2.4, 3.2, 4]` (default) | 1-by-n vector

Vector of C_v flow coefficients. Each coefficient corresponds to a value in the Control member position vector parameter. This parameter measures the ease with which the vapor traverses the resistive element when driven by a pressure differential. The size of the vector must be the same as the Control member position vector parameter.

Dependencies

Programmatic Use

Parameter: Cv_TLU

Maximum Kv flow coefficient — K_v coefficient that corresponds to maximally open component
`3.6` (default) | positive scalar

Value of the K_v flow coefficient when the orifice is fully open and the area available for flow is at a maximum. This parameter measures the ease with which the vapor traverses the resistive element when driven by a pressure differential.

Dependencies

To enable this parameter, set Modeling option to Vapor operating condition, Area characteristics to Identical for all flow paths, Orifice parameterization to Kv flow coefficient, and Opening characteristic to Linear.

Programmatic Use

Parameter: Kv_max

Kv flow coefficient vector — K_v coefficients for values in member position vector
`[1e-06, .72, 1.44, 2.16, 2.88, 3.6]` (default) | 1-by-n vector

Vector of K_v flow coefficients. Each coefficient corresponds to a value in the Control member position vector parameter. This parameter measures the ease with which the vapor traverses the resistive element when driven by a pressure differential. The size of the vector must be the same as the Control member position vector parameter.

Dependencies

To enable this parameter, set Modeling option to Vapor operating condition, Area characteristics to Identical for all flow paths, Orifice parameterization to Kv flow coefficient, and Opening characteristic to Tabulated.

Programmatic Use

Parameter: Kv_TLU

xT pressure differential ratio factor at choked flow — Ratio of pressure differentials
`0.7` (default) | positive scalar

Ratio between the inlet pressure, p_in, and the outlet pressure, p_out, defined as $(p_{i n} - p_{o u t}) / p_{i n}$ where choking first occurs.

Dependencies

To enable this parameter, Modeling option to Vapor operating condition, Area characteristics to Identical for all flow paths, and Orifice parameterization to Cv flow coefficient or Kv flow coefficient.

Programmatic Use

Parameter: xT_Cv

Parameter: xT_Kv

Discharge coefficient — Discharge coefficient
`0.64` (default) | positive scalar

Correction factor that accounts for discharge losses in theoretical flows.

Dependencies

To enable this parameter, set Modeling option to Vapor operating condition and Orifice parameterization to Orifice area or set Modeling option to Liquid operating condition and Orifice parameterization to either:

Linear - Area vs. spool travel
Tabulated data - Area vs. spool travel

Programmatic Use

Parameter: Cd

Leakage flow fraction — Ratio of flow rates
`1e-6` (default) | positive scalar

Ratio of the flow rate of the orifice when it is closed to when it is open.

Dependencies

To enable this parameter, set either:

Modeling option to Liquid operating condition and Orifice parameterization to Linear - Area vs. spool travel.
Modeling option to Vapor operating condition and Opening characteristic to Linear.

Programmatic Use

Parameter: leakage_fraction

Smoothing factor — Numerical smoothing factor
`0.01` (default) | positive scalar in the range of [0,1]

Continuous smoothing factor that introduces a layer of gradual change based on the flow response when the valve is in the near-open and near-closed positions. To increase the stability of your simulation in these regimes, set this parameter to a nonzero value less than one.

Dependencies

To enable this parameter, set Modeling option to Liquid operating condition and Orifice parametrization to Linear - area vs. spool travel or set Modeling option to Vapor operating condition and Opening characteristic to Linear.

Programmatic Use

Parameter: smoothing_factor

Pressure recovery — Whether to account for pressure increase in area expansions
`off` (default) | `on`

Whether to account for pressure increase when fluid flows from a region of smaller cross-sectional area to a region of larger cross-sectional area.

Dependencies

To enable this parameter, set Modeling option to Liquid operating condition and Orifice parameterization to either:

Linear - area vs. spool travel
Tabulated data - Area vs. spool travel

Programmatic Use

Parameter:	`pressure_recovery`
Values:	`"true"` \| `"false"`

Laminar flow pressure ratio — Laminar-turbulent transition pressure ratio
`0.999` (default) | positive scalar

Ratio of the orifice outlet pressure to orifice inlet pressure at which the fluid transitions between the laminar and turbulent regimes. The pressure loss corresponds to the mass flow rate linearly in laminar flows and quadratically in turbulent flows.

Programmatic Use

Parameter: B_lam

Inlet phase change time constant — Time lag for mixture specific volume
`0.1` `s` (default) | positive scalar

Time lag for liquid-vapor mixtures when computing the fluid specific volume. This parameter does not influence the specific volume when the inlet fluid is a fully supercooled liquid or fully superheated vapor.

Dependencies

To enable this parameter, set Modeling option to Liquid operating condition.

Programmatic Use

Parameter: tau_x

Cross-sectional area at ports P, T, A, and B — Area at conserving ports
`0.01 m^2` (default) | positive scalar

Maximum cross-sectional areas at the entry and exit ports P, T, A, and B, which the block uses in the pressure-flow rate equation that determines the mass flow rate through the valve.

Programmatic Use

Parameter: area

P-A Orifice

Spool position at maximum P-A orifice area — Spool offset for fully open P-A orifice
`5e-3 m` (default) | positive scalar

Spool offset from the neutral position for a fully open P-A orifice.

Dependencies

To enable this parameter, set one of these parameters.

Set Positive spool position open connections to:

P-A, B-T
P-A, P-B
P-A
P-A, P-B, A-T, B-T

or set Negative spool position open connections to:

P-A, B-T
P-A, P-B
P-A
P-A, P-B, A-T, B-T

Note:

This parameter is enabled only when the P-A orifice settings do not appear in both the Positive spool position open connections and Negative spool position open connections parameters.

Programmatic Use

Parameter: S_max_PA

P-A spool travel between closed and open orifice — Maximum spool stroke
`0.005 m` (default) | positive scalar

Maximum distance of spool travel. This value provides an upper limit to calculations so that simulations do not return unphysical values.

Dependencies

To enable this parameter, set one of the following parameters:

Positive spool position open connections to:

P-A, B-T
P-A, P-B
P-A
P-A, P-B, A-T, B-T

Negative spool position open connections to:

P-A, B-T
P-A, P-B
P-A
P-A, P-B, A-T, B-T

And either:

Modeling option to Liquid operating condition, Area characteristics to Different for each flow path, and Orifice parameterization to Linear - Area vs. spool travel or Linear - Nominal mass flow rate vs. spool travel.
Modeling option to Vapor operating condition, Area characteristics to Different for each flow path, and Opening characteristic to Linear.

Programmatic Use

Parameter: del_S_max_PA

P-A nominal mass flow rate at maximum orifice opening — Rated mass flow rate
`0.1` `kg/s` (default) | positive scalar

Typical, rated, or design mass flow rate through a maximally open P-A orifice.

Dependencies

To enable this parameter, set:

Modeling option to Liquid operating condition
Area characteristics to Different for each flow path
Orifice parameterization to Linear - Nominal mass flow rate vs. spool travel
One of the following parameters:
Positive spool position open connections to:
- P-A, B-T
- P-A, P-B
- P-A
- P-A, P-B, A-T, B-T
Negative spool position open connections to:
- P-A, B-T
- P-A, P-B
- P-A
- P-A, P-B, A-T, B-T

Programmatic Use

Parameter: mdot_nominal_max_PA

P-A nominal pressure drop at maximum orifice opening — Rated pressure drop
`0.001` `MPa` (default) | positive scalar

Typical, rated, or design pressure drop through a maximally open P-A orifice.

Dependencies

To enable this parameter, set:

Modeling option to Liquid operating condition
Area characteristics to Different for each flow path
Orifice parameterization to Linear - Nominal mass flow rate vs. spool travel
One of the following parameters:
Positive spool position open connections to:
- P-A, B-T
- P-A, P-B
- P-A
- P-A, P-B, A-T, B-T
Negative spool position open connections to:
- P-A, B-T
- P-A, P-B
- P-A
- P-A, P-B, A-T, B-T

Programmatic Use

Parameter: delta_p_nominal_max_PA

P-A nominal inlet condition specification — Method of determining inlet fluid state
`Temperature` (default) | `Vapor quality` | `Vapor void fraction` | `Specific enthalpy` | `Specific internal energy`

Method of determining the inlet fluid state for P-A orifice.

Dependencies

To enable this parameter, set:

Modeling option to Liquid operating condition
Area characteristics to Different for each flow path
Orifice parameterization to Linear - Nominal mass flow rate vs. spool travel
At least one of the following parameters:
Positive spool position open connections to:
- P-A, B-T
- P-A, P-B
- P-A
- P-A, P-B, A-T, B-T
Negative spool position open connections to:
- P-A, B-T
- P-A, P-B
- P-A
- P-A, P-B, A-T, B-T

Programmatic Use

Parameter:	`energy_spec_PA`
Values:	`"foundation.enum.energy_spec.temperature"` \| `"foundation.enum.energy_spec.quality"` \| `"foundation.enum.energy_spec.void_fraction"` \| `"foundation.enum.energy_spec.enthalpy"` \| `"foundation.enum.energy_spec.internal_energy"`

P-A nominal inlet pressure — Inlet fluid pressure
`0.101325` `MPa` (default) | positive scalar

Inlet pressure for the P-A orifice at nominal conditions.

Dependencies

To enable this parameter, set:

Modeling option to Liquid operating condition
Area characteristics to Different for each flow path
Orifice parameterization to Linear - Nominal mass flow rate vs. spool travel
At least one of the following parameters:
Positive spool position open connections to:
- P-A, B-T
- P-A, P-B
- P-A
- P-A, P-B, A-T, B-T
Negative spool position open connections to:
- P-A, B-T
- P-A, P-B
- P-A
- P-A, P-B, A-T, B-T

Programmatic Use

Parameter: p_inlet_PA

P-A nominal inlet temperature — Fluid temperature
`293.15` `K` (default) | positive scalar

Inlet fluid temperature for the P-A orifice in nominal operating conditions.

Dependencies

To enable this parameter, set:

Modeling option to Liquid operating condition
Area characteristics to Different for each flow path
Orifice parameterization to Linear - Nominal mass flow rate vs. spool travel
Nominal inlet condition specification to Temperature
At least one of the following parameters:
Positive spool position open connections to:
- P-A, B-T
- P-A, P-B
- P-A
- P-A, P-B, A-T, B-T
Negative spool position open connections to:
- P-A, B-T
- P-A, P-B
- P-A
- P-A, P-B, A-T, B-T

Programmatic Use

Parameter: T_inlet_PA

P-A nominal inlet vapor quality — Inlet vapor quality mass fraction
`0` (default) | positive scalar in the range [0,1]

Inlet mixture vapor quality by mass fraction for the P-A orifice in nominal operating conditions. A value of 0 means that the inlet fluid is subcooled liquid. A value of 1 means that the inlet fluid is superheated vapor.

Dependencies

To enable this parameter, set:

Modeling option to Liquid operating condition
Area characteristics to Different for each flow path
Orifice parameterization to Linear - Nominal mass flow rate vs. spool travel
Nominal inlet condition specification to Vapor quality
At least one of the following parameters:
Positive spool position open connections to:
- P-A, B-T
- P-A, P-B
- P-A
- P-A, P-B, A-T, B-T
Negative spool position open connections to:
- P-A, B-T
- P-A, P-B
- P-A
- P-A, P-B, A-T, B-T

Programmatic Use

Parameter: x_inlet_PA

P-A nominal inlet vapor void fraction — Inlet vapor void fraction
`0` (default) | positive scalar in the range [0,1]

Inlet mixture vapor void fraction for the P-A orifice in nominal operating conditions. A value of 0 means that the inlet fluid is subcooled liquid. A value of 1 means that the inlet fluid is superheated vapor.

Dependencies

To enable this parameter, set:

Modeling option to Liquid operating condition
Area characteristics to Different for each flow path
Orifice parameterization to Linear - Nominal mass flow rate vs. spool travel
Nominal inlet condition specification to Vapor void fraction
At least one of the following parameters:
Positive spool position open connections to:
- P-A, B-T
- P-A, P-B
- P-A
- P-A, P-B, A-T, B-T
Negative spool position open connections to:
- P-A, B-T
- P-A, P-B
- P-A
- P-A, P-B, A-T, B-T

Programmatic Use

Parameter: alpha_inlet_PA

P-A nominal inlet specific enthalpy — Inlet fluid specific enthalpy
`400` `kJ/kg` (default) | positive scalar

Inlet specific enthalpy for the P-A orifice in nominal operating conditions.

Dependencies

To enable this parameter, set:

Modeling option to Liquid operating condition
Area characteristics to Different for each flow path
Orifice parameterization to Linear - Nominal mass flow rate vs. spool travel
Nominal inlet condition specification to Specific enthalpy
At least one of the following parameters:
Positive spool position open connections to:
- P-A, B-T
- P-A, P-B
- P-A
- P-A, P-B, A-T, B-T
Negative spool position open connections to:
- P-A, B-T
- P-A, P-B
- P-A
- P-A, P-B, A-T, B-T

Programmatic Use

Parameter: h_inlet_PA

P-A nominal inlet specific internal energy — Inlet specific internal energy
`400` `kJ/kg` (default) | positive scalar

Inlet specific internal energy for the P-A orifice in nominal operating conditions.

Dependencies

To enable this parameter, set:

Modeling option to Liquid operating condition
Area characteristics to Different for each flow path
Orifice parameterization to Linear - Nominal mass flow rate vs. spool travel
Nominal inlet condition specification to Specific internal energy
At least one of the following parameters:
Positive spool position open connections to:
- P-A, B-T
- P-A, P-B
- P-A
- P-A, P-B, A-T, B-T
Negative spool position open connections to:
- P-A, B-T
- P-A, P-B
- P-A
- P-A, P-B, A-T, B-T

Programmatic Use

Parameter: u_inlet_PA

P-A constant orifice nominal mass flow rate — Nominal mass flow rate
`0.1` `kg/s` (default) | positive scalar

Typical, rated, or design mass flow rate through a constant P-A orifice.

Dependencies

To enable this parameter, set:

Modeling option to Liquid operating condition
Area characteristics to Different for each flow path
Orifice parameterization to Linear - Nominal mass flow rate vs. spool travel
One of the following settings in each parameter:
Positive spool position open connections to:
- P-A, B-T
- P-A, P-B
- P-A
- P-A, P-B, A-T, B-T
Negative spool position open connections to:
- P-A, B-T
- P-A, P-B
- P-A
- P-A, P-B, A-T, B-T

Note:

This parameter is enabled only when the P-A orifice settings appear in both the Positive spool position open connections and Negative spool position open connections parameters.

Programmatic Use

Parameter: mdot_nominal_const_PA

P-A constant orifice nominal pressure drop — Nominal pressure drop
`0.001` `MPa` (default) | positive scalar

Typical, rated, or design pressure drop through a constant P-A orifice.

Dependencies

To enable this parameter, set:

Modeling option to Liquid operating condition
Area characteristics to Different for each flow path
Orifice parameterization to Linear - Nominal mass flow rate vs. spool travel
One of the following settings in each parameter:
Positive spool position open connections to:
- P-A, B-T
- P-A, P-B
- P-A
- P-A, P-B, A-T, B-T
Negative spool position open connections to:
- P-A, B-T
- P-A, P-B
- P-A
- P-A, P-B, A-T, B-T

Note:

This parameter is enabled only when the P-A orifice settings appear in both the Positive spool position open connections and Negative spool position open connections parameters.

Programmatic Use

Parameter: delta_p_nominal_const_PA

P-A constant orifice Cv flow coefficient — Flow coefficient
`4` (default) | positive scalar

Value of the constant C_v flow coefficient for the P-A orifice. This parameter measures the ease with which the vapor traverses the resistive element when driven by a pressure differential.

Dependencies

To enable this parameter, set:

Modeling option to Vapor operating condition
Area characteristics to Different for each flow path
Orifice parameterization to Cv flow coefficient
One of the following settings in each parameter:
Positive spool position open connections to:
- P-A, B-T
- P-A, P-B
- P-A
- P-A, P-B, A-T, B-T
Negative spool position open connections to:
- P-A, B-T
- P-A, P-B
- P-A
- P-A, P-B, A-T, B-T

Note:

This parameter is enabled only when the P-A orifice settings appear in both the Positive spool position open connections and Negative spool position open connections parameters.

Programmatic Use

Parameter: Cv_const_PA

P-A orifice maximum Cv flow coefficient — C_v coefficient that corresponds to maximally open component
`4` (default) | positive scalar

Value of the C_v flow coefficient when the P-A orifice is fully open and the area available for flow is at a maximum. This parameter measures the ease with which the vapor traverses the resistive element when driven by a pressure differential.

Dependencies

To enable this parameter, set:

Modeling option to Vapor operating condition
Area characteristics to Different for each flow path
Orifice parameterization to Cv flow coefficient
Opening characteristic to Linear
One of the following parameters:
Positive spool position open connections to:
- P-A, B-T
- P-A, P-B
- P-A
- P-A, P-B, A-T, B-T
Negative spool position open connections to:
- P-A, B-T
- P-A, P-B
- P-A
- P-A, P-B, A-T, B-T

Programmatic Use

Parameter: Cv_max_PA

P-A orifice Cv flow coefficient vector — C_v coefficients for values in member position vector
`[1e-06, .8, 1.6, 2.4, 3.2, 4]` (default) | 1-by-n vector

Vector of C_v flow coefficients. Each coefficient corresponds to a value in the P-A orifice spool travel vector parameter. This parameter measures the ease with which the vapor traverses the resistive element when driven by a pressure differential. The size of the vector must be the same as the P-A orifice spool travel vector parameter.

Dependencies

To enable this parameter, set:

Modeling option to Vapor operating condition
Area characteristics to Different for each flow path
Orifice parameterization to Cv flow coefficient
Opening characteristic to Tabulated
One of the following parameters:
Positive spool position open connections to:
- P-A, B-T
- P-A, P-B
- P-A
- P-A, P-B, A-T, B-T
Negative spool position open connections to:
- P-A, B-T
- P-A, P-B
- P-A
- P-A, P-B, A-T, B-T

Programmatic Use

Parameter: Cv_TLU_PA

P-A constant orifice Kv flow coefficient — Flow coefficient
`3.6` (default) | positive scalar

Value of the constant K_v flow coefficient for the P-A orifice. This parameter measures the ease with which the vapor traverses the resistive element when driven by a pressure differential.

Dependencies

To enable this parameter, set:

Modeling option to Vapor operating condition
Area characteristics to Different for each flow path
Orifice parameterization to Kv flow coefficient
One of the following settings in each parameter:
Positive spool position open connections to:
- P-A, B-T
- P-A, P-B
- P-A
- P-A, P-B, A-T, B-T
Negative spool position open connections to:
- P-A, B-T
- P-A, P-B
- P-A
- P-A, P-B, A-T, B-T

Note:

This parameter is enabled only when the P-A orifice settings appear in both the Positive spool position open connections and Negative spool position open connections parameters.

Programmatic Use

Parameter: Kv_const_PA

P-A orifice maximum Kv flow coefficient — K_v coefficient that corresponds to maximally open component
`3.6` (default) | positive scalar

Value of the K_v flow coefficient when the P-A orifice is fully open and the area available for flow is at a maximum. This parameter measures the ease with which the vapor traverses the resistive element when driven by a pressure differential.

Dependencies

To enable this parameter, set:

Modeling option to Vapor operating condition
Area characteristics to Different for each flow path
Orifice parameterization to Kv flow coefficient
Opening characteristic to Linear
One of the following parameters:
Positive spool position open connections to:
- P-A, B-T
- P-A, P-B
- P-A
- P-A, P-B, A-T, B-T
Negative spool position open connections to:
- P-A, B-T
- P-A, P-B
- P-A
- P-A, P-B, A-T, B-T

Programmatic Use

Parameter: Kv_max_PA

P-A orifice Kv flow coefficient vector — K_v coefficients for values in member position vector
`[1e-06, .72, 1.44, 2.16, 2.88, 3.6]` (default) | 1-by-n vector

Vector of K_v flow coefficients. Each coefficient corresponds to a value in the P-A orifice spool travel vector parameter. This parameter measures the ease with which the vapor traverses the resistive element when driven by a pressure differential. The size of the vector must be the same as the P-A orifice spool travel vector parameter.

Dependencies

To enable this parameter, set:

Modeling option to Vapor operating condition
Area characteristics to Different for each flow path
Orifice parameterization to Kv flow coefficient
Opening characteristic to Tabulated
One of the following parameters:
Positive spool position open connections to:
- P-A, B-T
- P-A, P-B
- P-A
- P-A, P-B, A-T, B-T
Negative spool position open connections to:
- P-A, B-T
- P-A, P-B
- P-A
- P-A, P-B, A-T, B-T

Programmatic Use

Parameter: Kv_TLU_PA

P-A orifice spool travel vector — Vector of spool opening distances relative to fully closed position
`[0, .00125, .0025, .00375, .005] m` (default) | 1-by-n vector

Vector of spool travel distances for the tabular parameterization of the valve area. List the values in ascending order. The first element must be 0. The block uses linear interpolation between table data points.

Dependencies

To enable this parameter, set one of the following parameters:

Positive spool position open connections to:

P-A, B-T
P-A, P-B
P-A
P-A, P-B, A-T, B-T

Negative spool position open connections to:

P-A, B-T
P-A, P-B
P-A
P-A, P-B, A-T, B-T

And either:

Modeling option to Liquid operating condition, Area characteristics to Different for each flow path, and Orifice parameterization to Tabulated data - Area vs. spool travel.
Modeling option to Vapor operating condition, Area characteristics to Different for each flow path, and Opening characteristic to Tabulated.

Programmatic Use

Parameter: del_S_Cv_TLU_PA

Parameter: del_S_Kv_TLU_PA

Parameter: del_S_orifice_area_TLU_PA

Parameter: del_S_TLU_PA

P-A maximum orifice area — Maximum orifice opening area
`1e-4 m^2` (default) | positive scalar

Largest open area of the P-A orifice during the operation of the valve.

Dependencies

To enable this parameter, set one of the following parameters:

Positive spool position open connections to:

P-A, B-T
P-A, P-B
P-A
P-A, P-B, A-T, B-T

Negative spool position open connections to:

P-A, B-T
P-A, P-B
P-A
P-A, P-B, A-T, B-T

Also set Area characteristics to Different for each flow path and either:

Modeling option to Liquid operating condition and Orifice parameterization to Linear - Area vs. spool travel.
Modeling option to Vapor operating condition, Orifice parameterization to Orifice area, and Opening characteristic to Linear.

Programmatic Use

Parameter: orifice_area_max_PA

Parameter: valve_area_max_PA

P-A orifice area vector — Vector of valve opening areas
`[1e-10, 1e-05, 4e-05, 6e-05, .0001] m^2` (default) | 1-by-n vector

Vector of opening areas for the tabular parameterization of the valve area. The vector elements must correspond one-to-one with the elements in the P-A orifice spool travel vector parameter. The elements must be greater than 0 and listed in ascending order. The first element of this vector is the leakage area.

Dependencies

To enable this parameter, set one of the following parameters:

Positive spool position open connections to:

P-A, B-T
P-A, P-B
P-A
P-A, P-B, A-T, B-T

Negative spool position open connections to:

P-A, B-T
P-A, P-B
P-A
P-A, P-B, A-T, B-T

Also set Area characteristics to Different for each flow path and either:

Modeling option to Liquid operating condition and Orifice parameterization to Tabulated data - Area vs. spool travel.
Modeling option to Vapor operating condition, Orifice parameterization to Orifice area, and Opening characteristic to Tabulated.

Programmatic Use

Parameter: orifice_area_TLU_PA

Parameter: valve_area_TLU_PA

P-A constant orifice area — Cross-sectional area for constant orifice
`1e-4 m^2` (default) | positive scalar

Orifice area when the positive and negative spool positions include the same orifice.

Dependencies

To enable this parameter, set one of the following settings in each parameter:

Positive spool position open connections to:

P-A, B-T
P-A, P-B
P-A
P-A, P-B, A-T, B-T

Negative spool position open connections to:

P-A, B-T
P-A, P-B
P-A
P-A, P-B, A-T, B-T

And either:

Modeling option to Liquid operating condition, Area characteristics to Different for each flow path, and Orifice parameterization to Tabulated data - Area vs. spool travel or Linear - Area vs. spool travel.
Modeling option to Vapor operating condition, Area characteristics to Different for each flow path, and Opening characteristic to Tabulated.

Note:

This parameter is enabled only when the P-A orifice settings appear in both the Positive spool position open connections and Negative spool position open connections parameters.

Programmatic Use

Parameter: orifice_area_const_PA

Parameter: valve_area_const_PA

P-A orifice xT pressure differential ratio factor at choked flow — Ratio of pressure differentials
`0.7` (default) | positive scalar

Ratio between the inlet pressure, p_in, and the outlet pressure, p_out, defined as $(p_{i n} - p_{o u t}) / p_{i n}$ where choking first occurs for the P-A orifice.

Dependencies

To enable this parameter, set:

Modeling option to Vapor operating condition
Area characteristics to Different for each flow path
Orifice parameterization to Kv flow coefficient or Cv flow coefficient
At least one of the following parameters:
Positive spool position open connections to:
- P-A, B-T
- P-A, P-B
- P-A
- P-A, P-B, A-T, B-T
Negative spool position open connections to:
- P-A, B-T
- P-A, P-B
- P-A
- P-A, P-B, A-T, B-T

Programmatic Use

Parameter: xT_Cv_PA

Parameter: xT_Kv_PA

P-B Orifice

Spool position at maximum P-B orifice area — Spool offset for fully open P-B orifice
`5e-3 m` (default) | positive scalar

Spool offset from the neutral position for a fully open P-B orifice.

Dependencies

To enable this parameter, set one of these parameters:

Positive spool position open connections to:

P-B, A-T
P-A, P-B
P-B
P-A, P-B, A-T, B-T

or set Negative spool position open connections to:

P-B, A-T
P-A, P-B
P-B
P-A, P-B, A-T, B-T

Note:

This parameter is enabled only when the P-B orifice settings do not appear in both the Positive spool position open connections and Negative spool position open connections parameters.

Programmatic Use

Parameter: S_max_PB

P-B spool travel between closed and open orifice — Maximum spool stroke
`0.005 m` (default) | positive scalar

Maximum distance of spool travel. This value provides an upper limit to calculations so that simulations do not return unphysical values.

Dependencies

To enable this parameter, set one of the following parameters:

Positive spool position open connections to:

P-B, A-T
P-A, P-B
P-B
P-A, P-B, A-T, B-T

Negative spool position open connections to:

P-B, A-T
P-A, P-B
P-B
P-A, P-B, A-T, B-T

And either:

Modeling option to Liquid operating condition, Area characteristics to Different for each flow path, and Orifice parameterization to Linear - Area vs. spool travel or Linear - Nominal mass flow rate vs. spool travel.
Modeling option to Vapor operating condition, Area characteristics to Different for each flow path, and Opening characteristic to Linear.

Programmatic Use

Parameter: del_S_max_PB

P-B nominal mass flow rate at maximum orifice opening — Rated mass flow rate
`0.1` `kg/s` (default) | positive scalar

Typical, rated, or design mass flow rate through a maximally open P-B orifice.

Dependencies

To enable this parameter, set:

Modeling option to Liquid operating condition
Area characteristics to Different for each flow path
Orifice parameterization to Linear - Nominal mass flow rate vs. spool travel
One of the following parameters:
Positive spool position open connections to:
- P-B, A-T
- P-A, P-B
- P-B
- P-A, P-B, A-T, B-T
Negative spool position open connections to:
- P-B, A-T
- P-A, P-B
- P-B
- P-A, P-B, A-T, B-T

Programmatic Use

Parameter: mdot_nominal_max_PB

P-B nominal pressure drop at maximum orifice opening — Rated pressure drop
`0.001` `MPa` (default) | positive scalar

Typical, rated, or design pressure drop through a maximally open P-B orifice.

Dependencies

To enable this parameter, set:

Modeling option to Liquid operating condition
Area characteristics to Different for each flow path
Orifice parameterization to Linear - Nominal mass flow rate vs. spool travel
One of the following parameters:
Positive spool position open connections to:
- P-B, A-T
- P-A, P-B
- P-B
- P-A, P-B, A-T, B-T
Negative spool position open connections to:
- P-B, A-T
- P-A, P-B
- P-B
- P-A, P-B, A-T, B-T

Programmatic Use

Parameter: delta_p_nominal_max_PB

P-B nominal inlet condition specification — Method of determining inlet fluid state
`Temperature` (default) | `Vapor quality` | `Vapor void fraction` | `Specific enthalpy` | `Specific internal energy`

Method of determining the inlet fluid state for P-B orifice.

Dependencies

To enable this parameter, set:

Modeling option to Liquid operating condition
Area characteristics to Different for each flow path
Orifice parameterization to Linear - Nominal mass flow rate vs. spool travel
At least one of the following parameters:
Positive spool position open connections to:
- P-B, A-T
- P-A, P-B
- P-B
- P-A, P-B, A-T, B-T
Negative spool position open connections to:
- P-B, A-T
- P-A, P-B
- P-B
- P-A, P-B, A-T, B-T

Programmatic Use

Parameter:	`energy_spec_PB`
Values:	`"foundation.enum.energy_spec.temperature"` \| `"foundation.enum.energy_spec.quality"` \| `"foundation.enum.energy_spec.void_fraction"` \| `"foundation.enum.energy_spec.enthalpy"` \| `"foundation.enum.energy_spec.internal_energy"`

P-B nominal inlet pressure — Inlet fluid pressure
`0.101325` `MPa` (default) | positive scalar

Inlet pressure for the P-B orifice at nominal conditions.

Dependencies

To enable this parameter, set:

Modeling option to Liquid operating condition
Area characteristics to Different for each flow path
Orifice parameterization to Linear - Nominal mass flow rate vs. spool travel
At least one of the following parameters:
Positive spool position open connections to:
- P-B, A-T
- P-A, P-B
- P-B
- P-A, P-B, A-T, B-T
Negative spool position open connections to:
- P-B, A-T
- P-A, P-B
- P-B
- P-A, P-B, A-T, B-T

Programmatic Use

Parameter: p_inlet_PB

P-B nominal inlet temperature — Fluid temperature
`293.15` `K` (default) | positive scalar

Inlet fluid temperature for the P-B orifice in nominal operating conditions.

Dependencies

To enable this parameter, set:

Modeling option to Liquid operating condition
Area characteristics to Different for each flow path
Orifice parameterization to Linear - Nominal mass flow rate vs. spool travel
Nominal inlet condition specification to Temperature
At least one of the following parameters:
Positive spool position open connections to:
- P-B, A-T
- P-A, P-B
- P-B
- P-A, P-B, A-T, B-T
Negative spool position open connections to:
- P-B, A-T
- P-A, P-B
- P-B
- P-A, P-B, A-T, B-T

Programmatic Use

Parameter: T_inlet_PB

P-B nominal inlet vapor quality — Inlet vapor quality mass fraction
`0` (default) | positive scalar in the range [0,1]

Inlet mixture vapor quality by mass fraction for the P-B orifice in nominal operating conditions. A value of 0 means that the inlet fluid is subcooled liquid. A value of 1 means that the inlet fluid is superheated vapor.

Dependencies

To enable this parameter, set:

Modeling option to Liquid operating condition
Area characteristics to Different for each flow path
Orifice parameterization to Linear - Nominal mass flow rate vs. spool travel
Nominal inlet condition specification to Vapor quality
At least one of the following parameters:
Positive spool position open connections to:
- P-B, A-T
- P-A, P-B
- P-B
- P-A, P-B, A-T, B-T
Negative spool position open connections to:
- P-B, A-T
- P-A, P-B
- P-B
- P-A, P-B, A-T, B-T

Programmatic Use

Parameter: x_inlet_PB

P-B nominal inlet vapor void fraction — Inlet vapor void fraction
`0` (default) | positive scalar in the range [0,1]

Inlet mixture vapor void fraction for the P-B orifice in nominal operating conditions. A value of 0 means that the inlet fluid is subcooled liquid. A value of 1 means that the inlet fluid is superheated vapor.

Dependencies

To enable this parameter, set:

Modeling option to Liquid operating condition
Area characteristics to Different for each flow path
Orifice parameterization to Linear - Nominal mass flow rate vs. spool travel
Nominal inlet condition specification to Vapor void fraction
At least one of the following parameters:
Positive spool position open connections to:
- P-B, A-T
- P-A, P-B
- P-B
- P-A, P-B, A-T, B-T
Negative spool position open connections to:
- P-B, A-T
- P-A, P-B
- P-B
- P-A, P-B, A-T, B-T

Programmatic Use

Parameter: alpha_inlet_PB

P-B nominal inlet specific enthalpy — Inlet fluid specific enthalpy
`400` `kJ/kg` (default) | positive scalar

Inlet specific enthalpy for the P-B orifice in nominal operating conditions.

Dependencies

To enable this parameter, set:

Modeling option to Liquid operating condition
Area characteristics to Different for each flow path
Orifice parameterization to Linear - Nominal mass flow rate vs. spool travel
Nominal inlet condition specification to Specific enthalpy
At least one of the following parameters:
Positive spool position open connections to:
- P-B, A-T
- P-A, P-B
- P-B
- P-A, P-B, A-T, B-T
Negative spool position open connections to:
- P-B, A-T
- P-A, P-B
- P-B
- P-A, P-B, A-T, B-T

Programmatic Use

Parameter: h_inlet_PB

P-B nominal inlet specific internal energy — Inlet specific internal energy
`400` `kJ/kg` (default) | positive scalar

Inlet specific internal energy for the P-B orifice in nominal operating conditions.

Dependencies

To enable this parameter, set:

Modeling option to Liquid operating condition
Area characteristics to Different for each flow path
Orifice parameterization to Linear - Nominal mass flow rate vs. spool travel
Nominal inlet condition specification to Specific internal energy
At least one of the following parameters:
Positive spool position open connections to:
- P-B, A-T
- P-A, P-B
- P-B
- P-A, P-B, A-T, B-T
Negative spool position open connections to:
- P-B, A-T
- P-A, P-B
- P-B
- P-A, P-B, A-T, B-T

Programmatic Use

Parameter: u_inlet_PB

P-B constant orifice nominal mass flow rate — Nominal mass flow rate
`0.1` `kg/s` (default) | positive scalar

Typical, rated, or design mass flow rate through a constant P-B orifice.

Dependencies

To enable this parameter, set:

Modeling option to Liquid operating condition
Area characteristics to Different for each flow path
Orifice parameterization to Linear - Nominal mass flow rate vs. spool travel
One of the following settings in each parameter:
Positive spool position open connections to:
- P-B, A-T
- P-A, P-B
- P-B
- P-A, P-B, A-T, B-T
Negative spool position open connections to:
- P-B, A-T
- P-A, P-B
- P-B
- P-A, P-B, A-T, B-T

Note:

This parameter is enabled only when the P-B orifice settings appear in both the Positive spool position open connections and Negative spool position open connections parameters.

Programmatic Use

Parameter: mdot_nominal_const_PB

P-B constant orifice nominal pressure drop — Nominal pressure drop
`0.001` `MPa` (default) | positive scalar

Typical, rated, or design pressure drop through a constant P-B orifice.

Dependencies

To enable this parameter, set:

Modeling option to Liquid operating condition
Area characteristics to Different for each flow path
Orifice parameterization to Linear - Nominal mass flow rate vs. spool travel
One of the following settings in each parameter:
Positive spool position open connections to:
- P-B, A-T
- P-A, P-B
- P-B
- P-A, P-B, A-T, B-T
Negative spool position open connections to:
- P-B, A-T
- P-A, P-B
- P-B
- P-A, P-B, A-T, B-T

Note:

This parameter is enabled only when the P-B orifice settings appear in both the Positive spool position open connections and Negative spool position open connections parameters.

Programmatic Use

Parameter: delta_p_nominal_const_PB

P-B constant orifice Cv flow coefficient — Flow coefficient
`4` (default) | positive scalar

Value of the constant C_v flow coefficient for the P-B orifice. This parameter measures the ease with which the vapor traverses the resistive element when driven by a pressure differential.

Dependencies

To enable this parameter, set:

Modeling option to Vapor operating condition
Area characteristics to Different for each flow path
Orifice parameterization to Cv flow coefficient
One of the following settings in each parameter:
Positive spool position open connections to:
- P-B, A-T
- P-A, P-B
- P-B
- P-A, P-B, A-T, B-T
Negative spool position open connections to:
- P-B, A-T
- P-A, P-B
- P-B
- P-A, P-B, A-T, B-T

Note:

This parameter is enabled only when the P-B orifice settings appear in both the Positive spool position open connections and Negative spool position open connections parameters.

Programmatic Use

Parameter: Cv_const_PB

P-B orifice maximum Cv flow coefficient — C_v coefficient that corresponds to maximally open component
`4` (default) | positive scalar

Value of the C_v flow coefficient when the P-B orifice is fully open and the area available for flow is at a maximum. This parameter measures the ease with which the vapor traverses the resistive element when driven by a pressure differential.

Dependencies

To enable this parameter, set:

Modeling option to Vapor operating condition
Area characteristics to Different for each flow path
Orifice parameterization to Cv flow coefficient
Opening characteristic to Linear
One of the following parameters:
Positive spool position open connections to:
- P-B, A-T
- P-A, P-B
- P-B
- P-A, P-B, A-T, B-T
Negative spool position open connections to:
- P-B, A-T
- P-A, P-B
- P-B
- P-A, P-B, A-T, B-T

Programmatic Use

Parameter: Cv_max_PB

P-B orifice Cv flow coefficient vector — C_v coefficients for values in member position vector
`[1e-06, .8, 1.6, 2.4, 3.2, 4]` (default) | 1-by-n vector

Vector of C_v flow coefficients. Each coefficient corresponds to a value in the P-B orifice spool travel vector parameter. This parameter measures the ease with which the vapor traverses the resistive element when driven by a pressure differential. The size of the vector must be the same as the P-B orifice spool travel vector parameter.

Dependencies

To enable this parameter, set:

Modeling option to Vapor operating condition
Area characteristics to Different for each flow path
Orifice parameterization to Cv flow coefficient
Opening characteristic to Tabulated
One of the following parameters:
Positive spool position open connections to:
- P-B, A-T
- P-A, P-B
- P-B
- P-A, P-B, A-T, B-T
Negative spool position open connections to:
- P-B, A-T
- P-A, P-B
- P-B
- P-A, P-B, A-T, B-T

Programmatic Use

Parameter: Cv_TLU_PB

P-B constant orifice Kv flow coefficient — Flow coefficient
`3.6` (default) | positive scalar

Value of the constant K_v flow coefficient for the P-B orifice. This parameter measures the ease with which the vapor traverses the resistive element when driven by a pressure differential.

Dependencies

To enable this parameter, set:

Modeling option to Vapor operating condition
Area characteristics to Different for each flow path
Orifice parameterization to Kv flow coefficient
One of the following settings in each parameter:
Positive spool position open connections to:
- P-B, A-T
- P-A, P-B
- P-B
- P-A, P-B, A-T, B-T
Negative spool position open connections to:
- P-B, A-T
- P-A, P-B
- P-B
- P-A, P-B, A-T, B-T

Note:

This parameter is enabled only when the P-B orifice settings appear in both the Positive spool position open connections and Negative spool position open connections parameters.

Programmatic Use

Parameter: Kv_const_PB

P-B orifice maximum Kv flow coefficient — K_v coefficient that corresponds to maximally open component
`3.6` (default) | positive scalar

Value of the K_v flow coefficient when the P-B orifice is fully open and the area available for flow is at a maximum. This parameter measures the ease with which the vapor traverses the resistive element when driven by a pressure differential.

Dependencies

To enable this parameter, set:

Modeling option to Vapor operating condition
Area characteristics to Different for each flow path
Orifice parameterization to Kv flow coefficient
Opening characteristic to Linear
One of the following parameters:
Positive spool position open connections to:
- P-B, A-T
- P-A, P-B
- P-B
- P-A, P-B, A-T, B-T
Negative spool position open connections to:
- P-B, A-T
- P-A, P-B
- P-B
- P-A, P-B, A-T, B-T

Programmatic Use

Parameter: Kv_max_PB

P-B orifice Kv flow coefficient vector — K_v coefficients for values in member position vector
`[1e-06, .72, 1.44, 2.16, 2.88, 3.6]` (default) | 1-by-n vector

Vector of K_v flow coefficients. Each coefficient corresponds to a value in the P-B orifice spool travel vector parameter. This parameter measures the ease with which the vapor traverses the resistive element when driven by a pressure differential. The size of the vector must be the same as the P-B orifice spool travel vector parameter.

Dependencies

To enable this parameter, set:

Modeling option to Vapor operating condition
Area characteristics to Different for each flow path
Orifice parameterization to Kv flow coefficient
Opening characteristic to Tabulated
One of the following parameters:
Positive spool position open connections to:
- P-B, A-T
- P-A, P-B
- P-B
- P-A, P-B, A-T, B-T
Negative spool position open connections to:
- P-B, A-T
- P-A, P-B
- P-B
- P-A, P-B, A-T, B-T

Programmatic Use

Parameter: Kv_TLU_PB

P-B orifice spool travel vector — Vector of spool opening distances relative to fully closed position
`[0, .00125, .0025, .00375, .005] m` (default) | 1-by-n vector

Dependencies

To enable this parameter, set one of the following parameters:

Positive spool position open connections to:

P-B, A-T
P-A, P-B
P-B
P-A, P-B, A-T, B-T

Negative spool position open connections to:

P-B, A-T
P-A, P-B
P-B
P-A, P-B, A-T, B-T

And either:

Modeling option to Liquid operating condition, Area characteristics to Different for each flow path, and Orifice parameterization to Tabulated data - Area vs. spool travel.
Modeling option to Vapor operating condition, Area characteristics to Different for each flow path, and Opening characteristic to Tabulated.

Programmatic Use

Parameter: del_S_Cv_TLU_PB

Parameter: del_S_Kv_TLU_PB

Parameter: del_S_orifice_area_TLU_PB

Parameter: del_S_TLU_PB

P-B maximum orifice area — Maximum orifice opening area
`1e-4 m^2` (default) | positive scalar

Largest open area of the P-B orifice during the operation of the valve.

Dependencies

To enable this parameter, set one of the following parameters:

Positive spool position open connections to:

P-B, A-T
P-A, P-B
P-B
P-A, P-B, A-T, B-T

Negative spool position open connections to:

P-B, A-T
P-A, P-B
P-B
P-A, P-B, A-T, B-T

Also set Area characteristics to Different for each flow path and either:

Modeling option to Liquid operating condition and Orifice parameterization to Linear - Area vs. spool travel.
Modeling option to Vapor operating condition, Orifice parameterization to Orifice area, and Opening characteristic to Linear.

Programmatic Use

Parameter: orifice_area_max_PB

Parameter: valve_area_max_PB

P-B orifice area vector — Vector of valve opening areas
`[1e-10, 1e-05, 4e-05, 6e-05, .0001] m^2` (default) | 1-by-n vector

Vector of opening areas for the tabular parameterization of the valve area. The vector elements must correspond one-to-one with the elements in the P-B orifice spool travel vector parameter. The elements must be greater than 0 and listed in ascending order. The first element of this vector is the leakage area.

Dependencies

To enable this parameter, set one of the following parameters:

Positive spool position open connections to:

P-B, A-T
P-A, P-B
P-B
P-A, P-B, A-T, B-T

Negative spool position open connections to:

P-B, A-T
P-A, P-B
P-B
P-A, P-B, A-T, B-T

Also set Area characteristics to Different for each flow path and either:

Modeling option to Liquid operating condition and Orifice parameterization to Tabulated data - Area vs. spool travel.
Modeling option to Vapor operating condition, Orifice parameterization to Orifice area, and Opening characteristic to Tabulated.

Programmatic Use

Parameter: orifice_area_TLU_PB

Parameter: valve_area_TLU_PB

P-B constant orifice area — Cross-sectional area for constant orifice
`1e-4 m^2` (default) | positive scalar

Orifice area when the positive and negative spool positions include the same orifice.

Dependencies

To enable this parameter, set one of the following settings in each parameter:

Positive spool position open connections to:

P-B, A-T
P-A, P-B
P-B
P-A, P-B, A-T, B-T

Negative spool position open connections to:

P-B, A-T
P-A, P-B
P-B
P-A, P-B, A-T, B-T

And either:

Modeling option to Liquid operating condition, Area characteristics to Different for each flow path, and Orifice parameterization to Tabulated data - Area vs. spool travel or Linear - Area vs. spool travel.
Modeling option to Vapor operating condition, Area characteristics to Different for each flow path, and Opening characteristic to Tabulated.

Note:

This parameter is enabled only when the P-B orifice settings appear in both the Positive spool position open connections and Negative spool position open connections parameters.

Programmatic Use

Parameter: orifice_area_const_PB

Parameter: valve_area_const_PB

P-B orifice xT pressure differential ratio factor at choked flow — Ratio of pressure differentials
`0.7` (default) | positive scalar

Ratio between the inlet pressure, p_in, and the outlet pressure, p_out, defined as $(p_{i n} - p_{o u t}) / p_{i n}$ where choking first occurs for the P-B orifice.

Dependencies

To enable this parameter, set:

Modeling option to Vapor operating condition
Area characteristics to Different for each flow path
Orifice parameterization to Kv flow coefficient or Cv flow coefficient
At least one of the following parameters:
Positive spool position open connections to:
- P-B, A-T
- P-A, P-B
- P-B
- P-A, P-B, A-T, B-T
Negative spool position open connections to:
- P-B, A-T
- P-A, P-B
- P-B
- P-A, P-B, A-T, B-T

Programmatic Use

Parameter: xT_Cv_PB

Parameter: xT_Kv_PB

A-T Orifice

Spool position at maximum A-T orifice area — Spool offset for fully open A-T orifice
`5e-3 m` (default) | positive scalar

Spool offset from the neutral position for a fully open A-T orifice.

Dependencies

To enable this parameter, set one of these parameters.

Positive spool position open connections to P-B, A-T or P-A, P-B, A-T, B-T.
Negative spool position open connections to P-B, A-T or P-A, P-B, A-T, B-T.

Note:

This parameter is enabled only when the A-T orifice settings do not appear in both the Positive spool position open connections and Negative spool position open connections parameters.

Programmatic Use

Parameter: S_max_AT

A-T spool travel between closed and open orifice — Maximum spool stroke
`0.005 m` (default) | positive scalar

Maximum distance of spool travel. This value provides an upper limit to calculations so that simulations do not return unphysical values.

Dependencies

To enable this parameter, set one of the following parameters:

Positive spool position open connections to P-B, A-T or P-A, P-B, A-T, B-T.
Negative spool position open connections to P-B, A-T or P-A, P-B, A-T, B-T.

And either:

Modeling option to Liquid operating condition, Area characteristics to Different for each flow path, and Orifice parameterization to Linear - Area vs. spool travel or Linear - Nominal mass flow rate vs. spool travel.
Modeling option to Vapor operating condition, Area characteristics to Different for each flow path, and Opening characteristic to Linear.

Programmatic Use

Parameter: del_S_max_AT

A-T nominal mass flow rate at maximum orifice opening — Rated mass flow rate
`0.1` `kg/s` (default) | positive scalar

Typical, rated, or design mass flow rate through a maximally open A-T orifice.

Dependencies

To enable this parameter, set:

Modeling option to Liquid operating condition
Area characteristics to Different for each flow path
Orifice parameterization to Linear - Nominal mass flow rate vs. spool travel
One of the following parameters:
- Positive spool position open connections to P-B, A-T or P-A, P-B, A-T, B-T.
- Negative spool position open connections to P-B, A-T or P-A, P-B, A-T, B-T.

Programmatic Use

Parameter: mdot_nominal_max_AT

A-T nominal pressure drop at maximum orifice opening — Rated pressure drop
`0.001` `MPa` (default) | positive scalar

Typical, rated, or design pressure drop through a maximally open A-T orifice.

Dependencies

To enable this parameter, set:

Modeling option to Liquid operating condition
Area characteristics to Different for each flow path
Orifice parameterization to Linear - Nominal mass flow rate vs. spool travel
One of the following parameters:
- Positive spool position open connections to P-B, A-T or P-A, P-B, A-T, B-T.
- Negative spool position open connections to P-B, A-T or P-A, P-B, A-T, B-T.

Programmatic Use

Parameter: delta_p_nominal_max_AT

A-T nominal inlet condition specification — Method of determining inlet fluid state
`Temperature` (default) | `Vapor quality` | `Vapor void fraction` | `Specific enthalpy` | `Specific internal energy`

Method of determining the inlet fluid state for A-T orifice.

Dependencies

To enable this parameter, set:

Modeling option to Liquid operating condition
Area characteristics to Different for each flow path
Orifice parameterization to Linear - Nominal mass flow rate vs. spool travel
At least one of the following parameters:
- Positive spool position open connections to P-B, A-T or P-A, P-B, A-T, B-T.
- Negative spool position open connections to P-B, A-T or P-A, P-B, A-T, B-T.

Programmatic Use

Parameter:	`energy_spec_AT`
Values:	`"foundation.enum.energy_spec.temperature"` \| `"foundation.enum.energy_spec.quality"` \| `"foundation.enum.energy_spec.void_fraction"` \| `"foundation.enum.energy_spec.enthalpy"` \| `"foundation.enum.energy_spec.internal_energy"`

A-T nominal inlet pressure — Inlet fluid pressure
`0.101325` `MPa` (default) | positive scalar

Inlet pressure for the A-T orifice at nominal conditions.

Dependencies

To enable this parameter, set:

Modeling option to Liquid operating condition
Area characteristics to Different for each flow path
Orifice parameterization to Linear - Nominal mass flow rate vs. spool travel
At least one of the following parameters:
- Positive spool position open connections to P-B, A-T or P-A, P-B, A-T, B-T.
- Negative spool position open connections to P-B, A-T or P-A, P-B, A-T, B-T.

Programmatic Use

Parameter: p_inlet_AT

A-T nominal inlet temperature — Fluid temperature
`293.15` `K` (default) | positive scalar

Inlet fluid temperature for the A-T orifice in nominal operating conditions.

Dependencies

To enable this parameter, set:

Modeling option to Liquid operating condition
Area characteristics to Different for each flow path
Orifice parameterization to Linear - Nominal mass flow rate vs. spool travel
Nominal inlet condition specification to Temperature
At least one of the following parameters:
- Positive spool position open connections to P-B, A-T or P-A, P-B, A-T, B-T.
- Negative spool position open connections to P-B, A-T or P-A, P-B, A-T, B-T.

Programmatic Use

Parameter: T_inlet_AT

A-T nominal inlet vapor quality — Inlet vapor quality mass fraction
`0` (default) | positive scalar in the range [0,1]

Inlet mixture vapor quality by mass fraction for the A-T orifice in nominal operating conditions. A value of 0 means that the inlet fluid is subcooled liquid. A value of 1 means that the inlet fluid is superheated vapor.

Dependencies

To enable this parameter, set:

Modeling option to Liquid operating condition
Area characteristics to Different for each flow path
Orifice parameterization to Linear - Nominal mass flow rate vs. spool travel
Nominal inlet condition specification to Vapor quality
At least one of the following parameters:
- Positive spool position open connections to P-B, A-T or P-A, P-B, A-T, B-T.
- Negative spool position open connections to P-B, A-T or P-A, P-B, A-T, B-T.

Programmatic Use

Parameter: x_inlet_AT

A-T nominal inlet vapor void fraction — Inlet vapor void fraction
`0` (default) | positive scalar in the range [0,1]

Inlet mixture vapor void fraction for the A-T orifice in nominal operating conditions. A value of 0 means that the inlet fluid is subcooled liquid. A value of 1 means that the inlet fluid is superheated vapor.

Dependencies

To enable this parameter, set:

Modeling option to Liquid operating condition
Area characteristics to Different for each flow path
Orifice parameterization to Linear - Nominal mass flow rate vs. spool travel
Nominal inlet condition specification to Vapor void fraction
At least one of the following parameters:
- Positive spool position open connections to P-B, A-T or P-A, P-B, A-T, B-T.
- Negative spool position open connections to P-B, A-T or P-A, P-B, A-T, B-T.

Programmatic Use

Parameter: alpha_inlet_AT

A-T nominal inlet specific enthalpy — Inlet fluid specific enthalpy
`400` `kJ/kg` (default) | positive scalar

Inlet specific enthalpy for the A-T orifice in nominal operating conditions.

Dependencies

To enable this parameter, set:

Modeling option to Liquid operating condition
Area characteristics to Different for each flow path
Orifice parameterization to Linear - Nominal mass flow rate vs. spool travel
Nominal inlet condition specification to Specific enthalpy
At least one of the following parameters:
- Positive spool position open connections to P-B, A-T or P-A, P-B, A-T, B-T.
- Negative spool position open connections to P-B, A-T or P-A, P-B, A-T, B-T.

Programmatic Use

Parameter: h_inlet_AT

A-T nominal inlet specific internal energy — Inlet specific internal energy
`400` `kJ/kg` (default) | positive scalar

Inlet specific internal energy for the A-T orifice in nominal operating conditions.

Dependencies

To enable this parameter, set:

Modeling option to Liquid operating condition
Area characteristics to Different for each flow path
Orifice parameterization to Linear - Nominal mass flow rate vs. spool travel
Nominal inlet condition specification to Specific internal energy
At least one of the following parameters:
- Positive spool position open connections to P-B, A-T or P-A, P-B, A-T, B-T.
- Negative spool position open connections to P-B, A-T or P-A, P-B, A-T, B-T.

Programmatic Use

Parameter: u_inlet_AT

A-T constant orifice nominal mass flow rate — Nominal mass flow rate
`0.1` `kg/s` (default) | positive scalar

Typical, rated, or design mass flow rate through a constant A-T orifice.

Dependencies

To enable this parameter, set:

Modeling option to Liquid operating condition
Area characteristics to Different for each flow path
Orifice parameterization to Linear - Nominal mass flow rate vs. spool travel
One of the following settings in each parameter:
- Positive spool position open connections to P-B, A-T or P-A, P-B, A-T, B-T.
- Negative spool position open connections to P-B, A-T or P-A, P-B, A-T, B-T.

Note:

This parameter is enabled only when the A-T orifice settings appear in both the Positive spool position open connections and Negative spool position open connections parameters.

Programmatic Use

Parameter: mdot_nominal_const_AT

A-T constant orifice nominal pressure drop — Nominal pressure drop
`0.001` `MPa` (default) | positive scalar

Typical, rated, or design pressure drop through a constant A-T orifice.

Dependencies

To enable this parameter, set:

Modeling option to Liquid operating condition
Area characteristics to Different for each flow path
Orifice parameterization to Linear - Nominal mass flow rate vs. spool travel
One of the following settings in each parameter:
- Positive spool position open connections to P-B, A-T or P-A, P-B, A-T, B-T.
- Negative spool position open connections to P-B, A-T or P-A, P-B, A-T, B-T.

Note:

This parameter is enabled only when the A-T orifice settings appear in both the Positive spool position open connections and Negative spool position open connections parameters.

Programmatic Use

Parameter: delta_p_nominal_const_AT

A-T constant orifice Cv flow coefficient — Flow coefficient
`4` (default) | positive scalar

Value of the constant C_v flow coefficient for the A-T orifice. This parameter measures the ease with which the vapor traverses the resistive element when driven by a pressure differential.

Dependencies

To enable this parameter, set:

Modeling option to Vapor operating condition
Area characteristics to Different for each flow path
Orifice parameterization to Cv flow coefficient
One of the following settings in each parameter:
- Positive spool position open connections to P-B, A-T or P-A, P-B, A-T, B-T.
- Negative spool position open connections to P-B, A-T or P-A, P-B, A-T, B-T.

Note:

This parameter is enabled only when the A-T orifice settings appear in both the Positive spool position open connections and Negative spool position open connections parameters.

Programmatic Use

Parameter: Cv_const_AT

A-T orifice maximum Cv flow coefficient — C_v coefficient that corresponds to maximally open component
`4` (default) | positive scalar

Value of the C_v flow coefficient when the A-T orifice is fully open and the area available for flow is at a maximum. This parameter measures the ease with which the vapor traverses the resistive element when driven by a pressure differential.

Dependencies

To enable this parameter, set:

Modeling option to Vapor operating condition
Area characteristics to Different for each flow path
Orifice parameterization to Cv flow coefficient
Opening characteristic to Linear
One of the following parameters:
- Positive spool position open connections to P-B, A-T or P-A, P-B, A-T, B-T.
- Negative spool position open connections to P-B, A-T or P-A, P-B, A-T, B-T.

Programmatic Use

Parameter: Cv_max_AT

A-T orifice Cv flow coefficient vector — C_v coefficients for values in member position vector
`[1e-06, .8, 1.6, 2.4, 3.2, 4]` (default) | 1-by-n vector

Vector of C_v flow coefficients. Each coefficient corresponds to a value in the A-T orifice spool travel vector parameter. This parameter measures the ease with which the vapor traverses the resistive element when driven by a pressure differential. The size of the vector must be the same as the A-T orifice spool travel vector parameter.

Dependencies

To enable this parameter, set:

Modeling option to Vapor operating condition
Area characteristics to Different for each flow path
Orifice parameterization to Cv flow coefficient
Opening characteristic to Tabulated
One of the following parameters:
- Positive spool position open connections to P-B, A-T or P-A, P-B, A-T, B-T.
- Negative spool position open connections to P-B, A-T or P-A, P-B, A-T, B-T.

Programmatic Use

Parameter: Cv_TLU_AT

A-T constant orifice Kv flow coefficient — Flow coefficient
`3.6` (default) | positive scalar

Value of the constant K_v flow coefficient for the A-T orifice. This parameter measures the ease with which the vapor traverses the resistive element when driven by a pressure differential.

Dependencies

To enable this parameter, set:

Modeling option to Vapor operating condition
Area characteristics to Different for each flow path
Orifice parameterization to Kv flow coefficient
One of the following settings in each parameter:
- Positive spool position open connections to P-B, A-T or P-A, P-B, A-T, B-T.
- Negative spool position open connections to P-B, A-T or P-A, P-B, A-T, B-T.

Note:

This parameter is enabled only when the A-T orifice settings appear in both the Positive spool position open connections and Negative spool position open connections parameters.

Programmatic Use

Parameter: Kv_const_AT

A-T orifice maximum Kv flow coefficient — K_v coefficient that corresponds to maximally open component
`3.6` (default) | positive scalar

Value of the K_v flow coefficient when the A-T orifice is fully open and the area available for flow is at a maximum. This parameter measures the ease with which the vapor traverses the resistive element when driven by a pressure differential.

Dependencies

To enable this parameter, set:

Modeling option to Vapor operating condition
Area characteristics to Different for each flow path
Orifice parameterization to Kv flow coefficient
Opening characteristic to Linear
One of the following parameters:
- Positive spool position open connections to P-B, A-T or P-A, P-B, A-T, B-T.
- Negative spool position open connections to P-B, A-T or P-A, P-B, A-T, B-T.

Programmatic Use

Parameter: Kv_max_AT

A-T orifice Kv flow coefficient vector — K_v coefficients for values in member position vector
`[1e-06, .72, 1.44, 2.16, 2.88, 3.6]` (default) | 1-by-n vector

Vector of K_v flow coefficients. Each coefficient corresponds to a value in the A-T orifice spool travel vector parameter. This parameter measures the ease with which the vapor traverses the resistive element when driven by a pressure differential. The size of the vector must be the same as the A-T orifice spool travel vector parameter.

Dependencies

To enable this parameter, set:

Modeling option to Vapor operating condition
Area characteristics to Different for each flow path
Orifice parameterization to Kv flow coefficient
Opening characteristic to Tabulated
One of the following parameters:
- Positive spool position open connections to P-B, A-T or P-A, P-B, A-T, B-T.
- Negative spool position open connections to P-B, A-T or P-A, P-B, A-T, B-T.

Programmatic Use

Parameter: Kv_TLU_AT

A-T orifice spool travel vector — Vector of spool opening distances relative to fully closed position
`[0, .00125, .0025, .00375, .005] m` (default) | 1-by-n vector

Dependencies

To enable this parameter, set one of the following parameters:

Positive spool position open connections to P-B, A-T or P-A, P-B, A-T, B-T.
Negative spool position open connections to P-B, A-T or P-A, P-B, A-T, B-T.

And either:

Modeling option to Liquid operating condition, Area characteristics to Different for each flow path, and Orifice parameterization to Tabulated data - Area vs. spool travel.
Modeling option to Vapor operating condition, Area characteristics to Different for each flow path, and Opening characteristic to Tabulated.

Programmatic Use

Parameter: del_S_Cv_TLU_AT

Parameter: del_S_Kv_TLU_AT

Parameter: del_S_orifice_area_TLU_AT

Parameter: del_S_TLU_AT

A-T maximum orifice area — Maximum orifice opening area
`1e-4 m^2` (default) | positive scalar

Largest open area of the A-T orifice during the operation of the valve.

Dependencies

To enable this parameter, set one of the following parameters:

Positive spool position open connections to P-B, A-T or P-A, P-B, A-T, B-T.
Negative spool position open connections to P-B, A-T or P-A, P-B, A-T, B-T.

Also set Area characteristics to Different for each flow path and either:

Modeling option to Liquid operating condition and Orifice parameterization to Linear - Area vs. spool travel.
Modeling option to Vapor operating condition, Orifice parameterization to Orifice area, and Opening characteristic to Linear.

Programmatic Use

Parameter: orifice_area_max_AT

Parameter: valve_area_max_AT

A-T orifice area vector — Vector of valve opening areas
`[1e-10, 1e-05, 4e-05, 6e-05, .0001] m^2` (default) | 1-by-n vector

Vector of opening areas for the tabular parameterization of the valve area. The vector elements must correspond one-to-one with the elements in the A-T orifice spool travel vector parameter. The elements must be greater than 0 and listed in ascending order. The first element of this vector is the leakage area.

Dependencies

To enable this parameter, set one of the following parameters:

Positive spool position open connections to P-B, A-T or P-A, P-B, A-T, B-T.
Negative spool position open connections to P-B, A-T or P-A, P-B, A-T, B-T.

Also set Area characteristics to Different for each flow path and either:

Modeling option to Liquid operating condition and Orifice parameterization to Tabulated data - Area vs. spool travel.
Modeling option to Vapor operating condition, Orifice parameterization to Orifice area, and Opening characteristic to Tabulated.

Programmatic Use

Parameter: orifice_area_TLU_AT

Parameter: valve_area_TLU_AT

A-T constant orifice area — Cross-sectional area for constant orifice
`1e-4 m^2` (default) | positive scalar

Orifice area when the positive and negative spool positions include the same orifice.

Dependencies

To enable this parameter, set one of the following settings in each parameter:

Positive spool position open connections to P-B, A-T or P-A, P-B, A-T, B-T.
Negative spool position open connections to P-B, A-T or P-A, P-B, A-T, B-T.

And either:

Modeling option to Liquid operating condition, Area characteristics to Different for each flow path, and Orifice parameterization to Tabulated data - Area vs. spool travel or Linear - Area vs. spool travel.
Modeling option to Vapor operating condition, Area characteristics to Different for each flow path, and Opening characteristic to Tabulated.

Note:

This parameter is enabled only when the A-T orifice settings appear in both the Positive spool position open connections and Negative spool position open connections parameters.

Programmatic Use

Parameter: orifice_area_const_AT

Parameter: valve_area_const_AT

A-T orifice xT pressure differential ratio factor at choked flow — Ratio of pressure differentials
`0.7` (default) | positive scalar

Ratio between the inlet pressure, p_in, and the outlet pressure, p_out, defined as $(p_{i n} - p_{o u t}) / p_{i n}$ where choking first occurs for the A-T orifice.

Dependencies

To enable this parameter, set:

Modeling option to Vapor operating condition
Area characteristics to Different for each flow path
Orifice parameterization to Kv flow coefficient or Cv flow coefficient
At least one of the following parameters:
- Positive spool position open connections to P-B, A-T or P-A, P-B, A-T, B-T.
- Negative spool position open connections to P-B, A-T or P-A, P-B, A-T, B-T.

Programmatic Use

Parameter: xT_Cv_AT

Parameter: xT_Kv_AT

B-T Orifice

Spool position at maximum B-T orifice area — Spool offset for fully open B-T orifice
`5e-3 m` (default) | positive scalar

Spool offset from the neutral position for a fully open B-T orifice.

Dependencies

To enable this parameter, set one of these parameters.

Positive spool position open connections to P-A, B-T or P-A, P-B, A-T, B-T.
Negative spool position open connections to P-A, B-T or P-A, P-B, A-T, B-T.

Note:

This parameter is enabled only when the B-T orifice settings do not appear in both the Positive spool position open connections and Negative spool position open connections parameters.

Programmatic Use

Parameter: S_max_BT

B-T spool travel between closed and open orifice — Maximum spool stroke
`0.005 m` (default) | positive scalar

Maximum distance of spool travel. This value provides an upper limit to calculations so that simulations do not return unphysical values.

Dependencies

To enable this parameter, set one of the following parameters:

Positive spool position open connections to P-A, B-T or P-A, P-B, A-T, B-T.
Negative spool position open connections to P-A, B-T or P-A, P-B, A-T, B-T.

And either:

Modeling option to Liquid operating condition, Area characteristics to Different for each flow path, and Orifice parameterization to Linear - Area vs. spool travel or Linear - Nominal mass flow rate vs. spool travel.
Modeling option to Vapor operating condition, Area characteristics to Different for each flow path, and Opening characteristic to Linear.

Programmatic Use

Parameter: del_S_max_BT

B-T nominal mass flow rate at maximum orifice opening — Rated mass flow rate
`0.1` `kg/s` (default) | positive scalar

Typical, rated, or design mass flow rate through a maximally open B-T orifice.

Dependencies

To enable this parameter, set:

Modeling option to Liquid operating condition
Area characteristics to Different for each flow path
Orifice parameterization to Linear - Nominal mass flow rate vs. spool travel
One of the following parameters:
- Positive spool position open connections to P-A, B-T or P-A, P-B, A-T, B-T.
- Negative spool position open connections to P-A, B-T or P-A, P-B, A-T, B-T.

Programmatic Use

Parameter: mdot_nominal_max_BT

B-T nominal pressure drop at maximum orifice opening — Rated pressure drop
`0.001` `MPa` (default) | positive scalar

Typical, rated, or design pressure drop through a maximally open B-T orifice.

Dependencies

To enable this parameter, set:

Modeling option to Liquid operating condition
Area characteristics to Different for each flow path
Orifice parameterization to Linear - Nominal mass flow rate vs. spool travel
One of the following parameters:
- Positive spool position open connections to P-A, B-T or P-A, P-B, A-T, B-T.
- Negative spool position open connections to P-A, B-T or P-A, P-B, A-T, B-T.

Programmatic Use

Parameter: delta_p_nominal_max_BT

B-T nominal inlet condition specification — Method of determining inlet fluid state
`Temperature` (default) | `Vapor quality` | `Vapor void fraction` | `Specific enthalpy` | `Specific internal energy`

Method of determining the inlet fluid state for B-T orifice.

Dependencies

To enable this parameter, set:

Modeling option to Liquid operating condition
Area characteristics to Different for each flow path
Orifice parameterization to Linear - Nominal mass flow rate vs. spool travel
At least one of the following parameters:
- Positive spool position open connections to P-A, B-T or P-A, P-B, A-T, B-T.
- Negative spool position open connections to P-A, B-T or P-A, P-B, A-T, B-T.

Programmatic Use

Parameter:	`energy_spec_BT`
Values:	`"foundation.enum.energy_spec.temperature"` \| `"foundation.enum.energy_spec.quality"` \| `"foundation.enum.energy_spec.void_fraction"` \| `"foundation.enum.energy_spec.enthalpy"` \| `"foundation.enum.energy_spec.internal_energy"`

B-T nominal inlet pressure — Inlet fluid pressure
`0.101325` `MPa` (default) | positive scalar

Inlet pressure for the B-T orifice at nominal conditions.

Dependencies

To enable this parameter, set:

Modeling option to Liquid operating condition
Area characteristics to Different for each flow path
Orifice parameterization to Linear - Nominal mass flow rate vs. spool travel
At least one of the following parameters:
- Positive spool position open connections to P-A, B-T or P-A, P-B, A-T, B-T.
- Negative spool position open connections to P-A, B-T or P-A, P-B, A-T, B-T.

Programmatic Use

Parameter: p_inlet_BT

B-T nominal inlet temperature — Fluid temperature
`293.15` `K` (default) | positive scalar

Inlet fluid temperature for the B-T orifice in nominal operating conditions.

Dependencies

To enable this parameter, set:

Modeling option to Liquid operating condition
Area characteristics to Different for each flow path
Orifice parameterization to Linear - Nominal mass flow rate vs. spool travel
Nominal inlet condition specification to Temperature
At least one of the following parameters:
- Positive spool position open connections to P-A, B-T or P-A, P-B, A-T, B-T.
- Negative spool position open connections to P-A, B-T or P-A, P-B, A-T, B-T.

Programmatic Use

Parameter: T_inlet_BT

B-T nominal inlet vapor quality — Inlet vapor quality mass fraction
`0` (default) | positive scalar in the range [0,1]

Inlet mixture vapor quality by mass fraction for the B-T orifice in nominal operating conditions. A value of 0 means that the inlet fluid is subcooled liquid. A value of 1 means that the inlet fluid is superheated vapor.

Dependencies

To enable this parameter, set:

Modeling option to Liquid operating condition
Area characteristics to Different for each flow path
Orifice parameterization to Linear - Nominal mass flow rate vs. spool travel
Nominal inlet condition specification to Vapor quality
At least one of the following parameters:
- Positive spool position open connections to P-A, B-T or P-A, P-B, A-T, B-T.
- Negative spool position open connections to P-A, B-T or P-A, P-B, A-T, B-T.

Programmatic Use

Parameter: x_inlet_BT

B-T nominal inlet vapor void fraction — Inlet vapor void fraction
`0` (default) | positive scalar in the range [0,1]

Inlet mixture vapor void fraction for the B-T orifice in nominal operating conditions. A value of 0 means that the inlet fluid is subcooled liquid. A value of 1 means that the inlet fluid is superheated vapor.

Dependencies

To enable this parameter, set:

Modeling option to Liquid operating condition
Area characteristics to Different for each flow path
Orifice parameterization to Linear - Nominal mass flow rate vs. spool travel
Nominal inlet condition specification to Vapor void fraction
At least one of the following parameters:
- Positive spool position open connections to P-A, B-T or P-A, P-B, A-T, B-T.
- Negative spool position open connections to P-A, B-T or P-A, P-B, A-T, B-T.

Programmatic Use

Parameter: alpha_inlet_BT

B-T nominal inlet specific enthalpy — Inlet fluid specific enthalpy
`400` `kJ/kg` (default) | positive scalar

Inlet specific enthalpy for the B-T orifice in nominal operating conditions.

Dependencies

To enable this parameter, set:

Modeling option to Liquid operating condition
Area characteristics to Different for each flow path
Orifice parameterization to Linear - Nominal mass flow rate vs. spool travel
Nominal inlet condition specification to Specific enthalpy
At least one of the following parameters:
- Positive spool position open connections to P-A, B-T or P-A, P-B, A-T, B-T.
- Negative spool position open connections to P-A, B-T or P-A, P-B, A-T, B-T.

Programmatic Use

Parameter: h_inlet_BT

B-T nominal inlet specific internal energy — Inlet specific internal energy
`400` `kJ/kg` (default) | positive scalar

Inlet specific internal energy for the B-T orifice in nominal operating conditions.

Dependencies

To enable this parameter, set:

Modeling option to Liquid operating condition
Area characteristics to Different for each flow path
Orifice parameterization to Linear - Nominal mass flow rate vs. spool travel
Nominal inlet condition specification to Specific internal energy
At least one of the following parameters:
- Positive spool position open connections to P-A, B-T or P-A, P-B, A-T, B-T.
- Negative spool position open connections to P-A, B-T or P-A, P-B, A-T, B-T.

Programmatic Use

Parameter: u_inlet_BT

B-T constant orifice nominal mass flow rate — Nominal mass flow rate
`0.1` `kg/s` (default) | positive scalar

Typical, rated, or design mass flow rate through a constant B-T orifice.

Dependencies

To enable this parameter, set:

Modeling option to Liquid operating condition
Area characteristics to Different for each flow path
Orifice parameterization to Linear - Nominal mass flow rate vs. spool travel
One of the following settings in each parameter:
- Positive spool position open connections to P-A, B-T or P-A, P-B, A-T, B-T.
- Negative spool position open connections to P-A, B-T or P-A, P-B, A-T, B-T.

Note:

This parameter is enabled only when the B-T orifice settings appear in both the Positive spool position open connections and Negative spool position open connections parameters.

Programmatic Use

Parameter: mdot_nominal_const_BT

B-T constant orifice nominal pressure drop — Nominal pressure drop
`0.001` `MPa` (default) | positive scalar

Typical, rated, or design pressure drop through a constant B-T orifice.

Dependencies

To enable this parameter, set:

Modeling option to Liquid operating condition
Area characteristics to Different for each flow path
Orifice parameterization to Linear - Nominal mass flow rate vs. spool travel
One of the following settings in each parameter:
- Positive spool position open connections to P-A, B-T or P-A, P-B, A-T, B-T.
- Negative spool position open connections to P-A, B-T or P-A, P-B, A-T, B-T.

Note:

This parameter is enabled only when the B-T orifice settings appear in both the Positive spool position open connections and Negative spool position open connections parameters.

Programmatic Use

Parameter: delta_p_nominal_const_BT

B-T constant orifice Cv flow coefficient — Flow coefficient
`4` (default) | positive scalar

Value of the constant C_v flow coefficient for the B-T orifice. This parameter measures the ease with which the vapor traverses the resistive element when driven by a pressure differential.

Dependencies

To enable this parameter, set:

Modeling option to Vapor operating condition
Area characteristics to Different for each flow path
Orifice parameterization to Cv flow coefficient
One of the following settings in each parameter:
- Positive spool position open connections to P-A, B-T or P-A, P-B, A-T, B-T.
- Negative spool position open connections to P-A, B-T or P-A, P-B, A-T, B-T.

Note:

This parameter is enabled only when the B-T orifice settings appear in both the Positive spool position open connections and Negative spool position open connections parameters.

Programmatic Use

Parameter: Cv_const_BT

B-T orifice maximum Cv flow coefficient — C_v coefficient that corresponds to maximally open component
`4` (default) | positive scalar

Value of the C_v flow coefficient when the B-T orifice is fully open and the area available for flow is at a maximum. This parameter measures the ease with which the vapor traverses the resistive element when driven by a pressure differential.

Dependencies

To enable this parameter, set:

Modeling option to Vapor operating condition
Area characteristics to Different for each flow path
Orifice parameterization to Cv flow coefficient
Opening characteristic to Linear
One of the following parameters:
- Positive spool position open connections to P-A, B-T or P-A, P-B, A-T, B-T.
- Negative spool position open connections to P-A, B-T or P-A, P-B, A-T, B-T.

Programmatic Use

Parameter: Cv_max_BT

B-T orifice Cv flow coefficient vector — C_v coefficients for values in member position vector
`[1e-06, .8, 1.6, 2.4, 3.2, 4]` (default) | 1-by-n vector

Vector of C_v flow coefficients. Each coefficient corresponds to a value in the B-T orifice spool travel vector parameter. This parameter measures the ease with which the vapor traverses the resistive element when driven by a pressure differential. The size of the vector must be the same as the B-T orifice spool travel vector parameter.

Dependencies

To enable this parameter, set:

Modeling option to Vapor operating condition
Area characteristics to Different for each flow path
Orifice parameterization to Cv flow coefficient
Opening characteristic to Tabulated
One of the following parameters:
- Positive spool position open connections to P-A, B-T or P-A, P-B, A-T, B-T.
- Negative spool position open connections to P-A, B-T or P-A, P-B, A-T, B-T.

Programmatic Use

Parameter: Cv_TLU_BT

B-T constant orifice Kv flow coefficient — Flow coefficient
`3.6` (default) | positive scalar

Value of the constant K_v flow coefficient for the B-T orifice. This parameter measures the ease with which the vapor traverses the resistive element when driven by a pressure differential.

Dependencies

To enable this parameter, set:

Modeling option to Vapor operating condition
Area characteristics to Different for each flow path
Orifice parameterization to Kv flow coefficient
One of the following settings in each parameter:
- Positive spool position open connections to P-A, B-T or P-A, P-B, A-T, B-T.
- Negative spool position open connections to P-A, B-T or P-A, P-B, A-T, B-T.

Note:

This parameter is enabled only when the B-T orifice settings appear in both the Positive spool position open connections and Negative spool position open connections parameters.

Programmatic Use

Parameter: Kv_const_BT

B-T orifice maximum Kv flow coefficient — K_v coefficient that corresponds to maximally open component
`3.6` (default) | positive scalar

Value of the K_v flow coefficient when the B-T orifice is fully open and the area available for flow is at a maximum. This parameter measures the ease with which the vapor traverses the resistive element when driven by a pressure differential.

Dependencies

To enable this parameter, set:

Modeling option to Vapor operating condition
Area characteristics to Different for each flow path
Orifice parameterization to Kv flow coefficient
Opening characteristic to Linear
One of the following parameters:
- Positive spool position open connections to P-A, B-T or P-A, P-B, A-T, B-T.
- Negative spool position open connections to P-A, B-T or P-A, P-B, A-T, B-T.

Programmatic Use

Parameter: Kv_max_BT

B-T orifice Kv flow coefficient vector — K_v coefficients for values in member position vector
`[1e-06, .72, 1.44, 2.16, 2.88, 3.6]` (default) | 1-by-n vector

Vector of K_v flow coefficients. Each coefficient corresponds to a value in the B-T orifice spool travel vector parameter. This parameter measures the ease with which the vapor traverses the resistive element when driven by a pressure differential. The size of the vector must be the same as the B-T orifice spool travel vector parameter.

Dependencies

To enable this parameter, set:

Modeling option to Vapor operating condition
Area characteristics to Different for each flow path
Orifice parameterization to Kv flow coefficient
Opening characteristic to Tabulated
One of the following parameters:
- Positive spool position open connections to P-A, B-T or P-A, P-B, A-T, B-T.
- Negative spool position open connections to P-A, B-T or P-A, P-B, A-T, B-T.

Programmatic Use

Parameter: Kv_TLU_BT

B-T orifice spool travel vector — Vector of spool opening distances relative to fully closed position
`[0, .00125, .0025, .00375, .005] m` (default) | 1-by-n vector

Dependencies

To enable this parameter, set one of the following parameters:

Positive spool position open connections to P-A, B-T or P-A, P-B, A-T, B-T.
Negative spool position open connections to P-A, B-T or P-A, P-B, A-T, B-T.

And either:

Modeling option to Liquid operating condition, Area characteristics to Different for each flow path, and Orifice parameterization to Tabulated data - Area vs. spool travel.
Modeling option to Vapor operating condition, Area characteristics to Different for each flow path, and Opening characteristic to Tabulated.

Programmatic Use

Parameter: del_S_Cv_TLU_BT

Parameter: del_S_Kv_TLU_BT

Parameter: del_S_orifice_area_TLU_BT

Parameter: del_S_TLU_BT

B-T maximum orifice area — Maximum orifice opening area
`1e-4 m^2` (default) | positive scalar

Largest open area of the B-T orifice during the operation of the valve.

Dependencies

To enable this parameter, set one of the following parameters:

Positive spool position open connections to P-A, B-T or P-A, P-B, A-T, B-T.
Negative spool position open connections to P-A, B-T or P-A, P-B, A-T, B-T.

Also set Area characteristics to Different for each flow path and either:

Modeling option to Liquid operating condition and Orifice parameterization to Linear - Area vs. spool travel.
Modeling option to Vapor operating condition, Orifice parameterization to Orifice area, and Opening characteristic to Linear.

Programmatic Use

Parameter: orifice_area_max_BT

Parameter: valve_area_max_BT

B-T orifice area vector — Vector of valve opening areas
`[1e-10, 1e-05, 4e-05, 6e-05, .0001] m^2` (default) | 1-by-n vector

Vector of opening areas for the tabular parameterization of the valve area. The vector elements must correspond one-to-one with the elements in the B-T orifice spool travel vector parameter. The elements must be greater than 0 and listed in ascending order. The first element of this vector is the leakage area.

Dependencies

To enable this parameter, set one of the following parameters:

Positive spool position open connections to P-A, B-T or P-A, P-B, A-T, B-T.
Negative spool position open connections to P-A, B-T or P-A, P-B, A-T, B-T.

Also set Area characteristics to Different for each flow path and either:

Modeling option to Liquid operating condition and Orifice parameterization to Tabulated data - Area vs. spool travel.
Modeling option to Vapor operating condition, Orifice parameterization to Orifice area, and Opening characteristic to Tabulated.

Programmatic Use

Parameter: orifice_area_TLU_BT

Parameter: valve_area_TLU_BT

B-T constant orifice area — Cross-sectional area for constant orifice
`1e-4 m^2` (default) | positive scalar

Orifice area when the positive and negative spool positions include the same orifice.

Dependencies

To enable this parameter, set one of the following settings in each parameter:

Positive spool position open connections to P-A, B-T or P-A, P-B, A-T, B-T.
Negative spool position open connections to P-A, B-T or P-A, P-B, A-T, B-T.

And either:

Modeling option to Liquid operating condition, Area characteristics to Different for each flow path, and Orifice parameterization to Tabulated data - Area vs. spool travel or Linear - Area vs. spool travel.
Modeling option to Vapor operating condition, Area characteristics to Different for each flow path, and Opening characteristic to Tabulated.

Note:

This parameter is enabled only when the B-T orifice settings appear in both the Positive spool position open connections and Negative spool position open connections parameters.

Programmatic Use

Parameter: orifice_area_const_BT

Parameter: valve_area_const_BT

B-T orifice xT pressure differential ratio factor at choked flow — Ratio of pressure differentials
`0.7` (default) | positive scalar

Ratio between the inlet pressure, p_in, and the outlet pressure, p_out, defined as $(p_{i n} - p_{o u t}) / p_{i n}$ where choking first occurs for the B-T orifice.

Dependencies

To enable this parameter, set:

Modeling option to Vapor operating condition
Area characteristics to Different for each flow path
Orifice parameterization to Kv flow coefficient or Cv flow coefficient
At least one of the following parameters:
- Positive spool position open connections to P-A, B-T or P-A, P-B, A-T, B-T.
- Negative spool position open connections to P-A, B-T or P-A, P-B, A-T, B-T.

Programmatic Use

Parameter: xT_Cv_BT

Parameter: xT_Kv_BT

Plots

Valve characteristics — Generate valve characteristics plot
button

Use the Plot button to generate the valve characteristics plot.

Extended Capabilities

expand all

C/C++ Code Generation
Generate C and C++ code using Simulink® Coder™.

Version History

Introduced in R2024b

4-Way 2-Position Directional Valve (2P)

Description

Spool Displacement and Valve Configuration

Valve Orifice Parameterizations

Visualize Orifice Openings

Assumptions and Limitations

Ports

Conserving

A — Entry or exit port two-phase fluid

Programmatic Use

B — Entry or exit port two-phase fluid

Programmatic Use

P — Entry or exit port two-phase fluid

Programmatic Use

T — Entry or exit port two-phase fluid

Programmatic Use

Input

S — Spool displacement, m physical signal

Programmatic Use

Parameters

Modeling option — Modeling option for fluid phase Liquid operating condition (default) | Vapor operating condition

Programmatic Use

Valve Configuration

Positive spool position open connections — Flow paths open when spool is in positive position P-A, B-T (default) | P-A, P-B | P-B, A-T | P-A | P-B | P-A, P-B, A-T, B-T

Programmatic Use

Negative spool position open connections — Flow paths open when spool moves in negative direction P-B, A-T (default) | P-A, B-T | P-A, P-B | P-A | P-B | P-A, P-B, A-T, B-T

Programmatic Use

Model Parameterization

Area characteristics — Flow equations for orifices Identical for all flow paths (default) | Different for each flow path

Programmatic Use

Orifice parameterization — Variable or constant orifice parameterization Linear - Area vs. spool travel (default) | Linear - Nominal mass flow rate vs. spool travel | Tabulated data - Area vs. spool travel | Cv flow coefficient | Kv flow coefficient | Orifice area

Programmatic Use

Spool travel between closed and open orifice — Maximum spool stroke 0.005 m (default) | positive scalar

Dependencies

Programmatic Use

Maximum orifice area — Maximum orifice opening area 1e-4 m^2 (default) | positive scalar

Dependencies

Programmatic Use

Nominal mass flow rate at maximum orifice opening — Rated mass flow rate 0.1 kg/s (default) | positive scalar

Dependencies

Programmatic Use

Nominal pressure drop at maximum orifice opening — Rated pressure drop 0.001 MPa (default) | positive scalar

Dependencies

Programmatic Use

Nominal inlet condition specification — Method of determining inlet fluid state Temperature (default) | Vapor quality | Vapor void fraction | Specific enthalpy | Specific internal energy

Dependencies

Programmatic Use

Nominal inlet pressure — Inlet fluid pressure 0.101325 MPa (default) | positive scalar

Dependencies

Programmatic Use

Nominal inlet temperature — Fluid temperature 293.15 K (default) | positive scalar

Dependencies

Programmatic Use

Nominal inlet vapor quality — Inlet vapor quality mass fraction 0 (default) | positive scalar in the range [0,1]

Dependencies

Programmatic Use

Nominal inlet vapor void fraction — Inlet volume fraction 0 (default) | positive scalar in the range [0,1]

Dependencies

Programmatic Use

Nominal inlet specific enthalpy — Inlet fluid specific enthalpy 400 kJ/kg (default) | positive scalar

Dependencies

Programmatic Use

Nominal inlet specific internal energy — Inlet specific internal energy 400 kJ/kg (default) | positive scalar

Dependencies

Programmatic Use

Opening characteristic — Method to convert control signal to measure of flow capacity Linear (default) | Tabulated

Dependencies

Programmatic Use

Spool travel vector — Vector of spool opening distances relative to fully closed position [0, .00125, .0025, .00375, .005] m (default) | 1-by-n vector

Dependencies

Programmatic Use

Orifice area vector — Vector of valve opening areas [1e-10, 1e-05, 4e-05, 6e-05, .0001] m^2 (default) | 1-by-n vector

Dependencies

Programmatic Use

Maximum Cv flow coefficient — Cv coefficient that corresponds to maximally open component 4 (default) | positive scalar

Dependencies

Programmatic Use

Cv flow coefficient vector — Cv coefficients for values in member position vector [1e-06, .8, 1.6, 2.4, 3.2, 4] (default) | 1-by-n vector

Dependencies

Programmatic Use

A — Entry or exit port
two-phase fluid

B — Entry or exit port
two-phase fluid

P — Entry or exit port
two-phase fluid

T — Entry or exit port
two-phase fluid

S — Spool displacement, m
physical signal

Modeling option — Modeling option for fluid phase
`Liquid operating condition` (default) | `Vapor operating condition`

Positive spool position open connections — Flow paths open when spool is in positive position
`P-A, B-T` (default) | `P-A, P-B` | `P-B, A-T` | `P-A` | `P-B` | `P-A, P-B, A-T, B-T`

Negative spool position open connections — Flow paths open when spool moves in negative direction
`P-B, A-T` (default) | `P-A, B-T` | `P-A, P-B` | `P-A` | `P-B` | `P-A, P-B, A-T, B-T`

Area characteristics — Flow equations for orifices
`Identical for all flow paths` (default) | `Different for each flow path`

Orifice parameterization — Variable or constant orifice parameterization
`Linear - Area vs. spool travel` (default) | `Linear - Nominal mass flow rate vs. spool travel` | `Tabulated data - Area vs. spool travel` | `Cv flow coefficient` | `Kv flow coefficient` | `Orifice area`

Spool travel between closed and open orifice — Maximum spool stroke
`0.005 m` (default) | positive scalar

Maximum orifice area — Maximum orifice opening area
`1e-4 m^2` (default) | positive scalar

Nominal mass flow rate at maximum orifice opening — Rated mass flow rate
`0.1` kg/s (default) | positive scalar

Nominal pressure drop at maximum orifice opening — Rated pressure drop
`0.001` MPa (default) | positive scalar

Nominal inlet condition specification — Method of determining inlet fluid state
`Temperature` (default) | `Vapor quality` | `Vapor void fraction` | `Specific enthalpy` | `Specific internal energy`

Nominal inlet pressure — Inlet fluid pressure
`0.101325` MPa (default) | positive scalar

Nominal inlet temperature — Fluid temperature
`293.15` K (default) | positive scalar

Nominal inlet vapor quality — Inlet vapor quality mass fraction
`0` (default) | positive scalar in the range [0,1]

Nominal inlet vapor void fraction — Inlet volume fraction
`0` (default) | positive scalar in the range [0,1]

Nominal inlet specific enthalpy — Inlet fluid specific enthalpy
`400` kJ/kg (default) | positive scalar

Nominal inlet specific internal energy — Inlet specific internal energy
`400` kJ/kg (default) | positive scalar

Opening characteristic — Method to convert control signal to measure of flow capacity
`Linear` (default) | `Tabulated`

Spool travel vector — Vector of spool opening distances relative to fully closed position
`[0, .00125, .0025, .00375, .005] m` (default) | 1-by-n vector

Orifice area vector — Vector of valve opening areas
`[1e-10, 1e-05, 4e-05, 6e-05, .0001] m^2` (default) | 1-by-n vector

Maximum Cv flow coefficient — C_v coefficient that corresponds to maximally open component
`4` (default) | positive scalar

Cv flow coefficient vector — C_v coefficients for values in member position vector
`[1e-06, .8, 1.6, 2.4, 3.2, 4]` (default) | 1-by-n vector

Maximum Kv flow coefficient — K_v coefficient that corresponds to maximally open component
`3.6` (default) | positive scalar

Kv flow coefficient vector — K_v coefficients for values in member position vector
`[1e-06, .72, 1.44, 2.16, 2.88, 3.6]` (default) | 1-by-n vector

xT pressure differential ratio factor at choked flow — Ratio of pressure differentials
`0.7` (default) | positive scalar

Discharge coefficient — Discharge coefficient
`0.64` (default) | positive scalar

Leakage flow fraction — Ratio of flow rates
`1e-6` (default) | positive scalar

Smoothing factor — Numerical smoothing factor
`0.01` (default) | positive scalar in the range of [0,1]

Pressure recovery — Whether to account for pressure increase in area expansions
`off` (default) | `on`

Laminar flow pressure ratio — Laminar-turbulent transition pressure ratio
`0.999` (default) | positive scalar

Inlet phase change time constant — Time lag for mixture specific volume
`0.1` `s` (default) | positive scalar

Cross-sectional area at ports P, T, A, and B — Area at conserving ports
`0.01 m^2` (default) | positive scalar

Spool position at maximum P-A orifice area — Spool offset for fully open P-A orifice
`5e-3 m` (default) | positive scalar

P-A spool travel between closed and open orifice — Maximum spool stroke
`0.005 m` (default) | positive scalar

P-A nominal mass flow rate at maximum orifice opening — Rated mass flow rate
`0.1` `kg/s` (default) | positive scalar

P-A nominal pressure drop at maximum orifice opening — Rated pressure drop
`0.001` `MPa` (default) | positive scalar

P-A nominal inlet condition specification — Method of determining inlet fluid state
`Temperature` (default) | `Vapor quality` | `Vapor void fraction` | `Specific enthalpy` | `Specific internal energy`

P-A nominal inlet pressure — Inlet fluid pressure
`0.101325` `MPa` (default) | positive scalar

P-A nominal inlet temperature — Fluid temperature
`293.15` `K` (default) | positive scalar

P-A nominal inlet vapor quality — Inlet vapor quality mass fraction
`0` (default) | positive scalar in the range [0,1]

P-A nominal inlet vapor void fraction — Inlet vapor void fraction
`0` (default) | positive scalar in the range [0,1]

P-A nominal inlet specific enthalpy — Inlet fluid specific enthalpy
`400` `kJ/kg` (default) | positive scalar

P-A nominal inlet specific internal energy — Inlet specific internal energy
`400` `kJ/kg` (default) | positive scalar

P-A constant orifice nominal mass flow rate — Nominal mass flow rate
`0.1` `kg/s` (default) | positive scalar

P-A constant orifice nominal pressure drop — Nominal pressure drop
`0.001` `MPa` (default) | positive scalar

P-A constant orifice Cv flow coefficient — Flow coefficient
`4` (default) | positive scalar