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M-Way N-Position Directional Valve (IL)

M-way, N-position valve in an isothermal liquid network

Since R2022b

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  • M-Way N-Position Directional Valve (IL) block

Libraries:
Simscape / Fluids / Isothermal Liquid / Valves & Orifices / Directional Control Valves

Description

The M-Way N-Position Directional Valve (IL) block represents a spool-operated directional valve with an arbitrary configuration of ports, spool positions, and orifices. The block accepts up to ten ports, ten spool positions, and 20 orifices. Valves with many configurations are most common in construction, agriculture, and some vehicle applications. This block simplifies complex parameterizations by allowing you to apply the same area characteristics to all flow paths. You can also individually specify the area characteristics for each flow path. You can parameterize the valve by specifying the opening area with tabulated or linear data or by using tabulated data that represents volumetric flow rate for a fully open orifice at varied pressure drops. The block uses a variable orifice to control the flow between a given pair of connected ports. The physical signal at port S triggers the spool motion to open or shut the valve. For more details about how the block calculates flow rate through a variable orifice, see Orifice (IL).

You can generate a characteristic plot of the valve by right-clicking the block and selecting Fluids > Plot Valve Characteristics. To updated the plot after changing the block parameters, click the Reload Data button. You can control the shape of the characteristic plot. To select which lines are visible, click the appropriate orifice on the legend.

The default valve characteristic plot is:

Default valve characteristic plot

The figure indicates locations A1, A2, B1, and B2.

Valve characteristic plot with points A1, B1, B2, and A2 labeled.

Position 1 is at spool travel of -1 mm. Position 2 is at spool travel of 0 mm, and Position 3 is at spool travel of 1 mm. Locations A1 and A2 represent the left- and right-side transition regions of the orifice opening area, respectively. Locations B1 and B2 represent the left- and right-side fully open regions of the orifice opening area, respectively. The current spool position is the separation between B1 and B2. When you set Area characteristics to Identical for all flow paths.

  • A1 = (distance between spool positions 1 and 2) * (value of the Inter-position spool travel fraction for which orifices transition between open-closed parameter)

  • A2 = (distance between spool positions 2 and 3) * (value of the Inter-position spool travel fraction for which orifices transition between open-closed parameter)

  • B1 = (distance between spool positions 1 and 2) * (value of the Inter-position spool travel fraction for which orifices remain fully open parameter)

  • B2 = (distance between spool positions 2 and 3) * (value of the Inter-position spool travel fraction for which orifices remain fully open parameter)

When you set Area characteristics to Different for each flow path and Orifice parameterization to Linear – Area vs. spool travel or Tabulated data – Volumetric flow rate vs. pressure drop (linear with spool travel):

  • A1 = A2 = value of the Spool travel for which orifice 2 transitions between open-closed parameter.

  • B1 = B2 = value of the Spool travel for which orifice 2 remains fully open parameter.

Orifice Parameterization

When you set Area parameterization to Different for each flow path, you can parameterize each orifice by using the parameters in the Orifice 1,…,20 sections. For example, if you set Number of orifices to 3, the block includes sections for Orifice 1, Orifice 2, and Orifice 3. Each section has the same parameter names followed by the number for that section.

The block icon updates automatically to indicate the orifice configuration, which you control with the appropriate Ports connected by orifice... parameter. If you connect one odd-numbered port to one even-numbered port, the block icon shows an arrow that points to the second listed port. The block icon indicates when a parameterization is invalid.

If you enable logging, the Orifice.S signal for each orifice describes the spool position according to this table:

 Area characteristic parameter
 Identical for all flow pathsDifferent for each flow path
If Orifice parameterization is Linear – Area vs. spool travel or Tabulated data – Volumetric flow rate vs. pressure drop (linear with spool travel)

Orifice.S = 0 m when the orifice is fully open. The units m in the Orifice.S signal correspond to the inter-position spool travel fraction.

Orifice.S = - Stravel when the orifice is fully closed where Stravel is the value of the Inter-position spool travel fraction for which orifices transition between open-closed parameter.

Orifice.S = 0 m when the orifice is fully open.

Orifice.S = - Stravel when the orifice is fully closed where Stravel is the value of the Spool travel for which orifice transitions between open-closed parameter.

If Orifice parameterization is Tabulated data – Area vs. spool travelNot a parameterization option

Orifice.S = 0 m when the orifice is fully open.

In all other positions, Orifice.S = the first or last element of an extended version of the Vector of spool travel relative to discrete spool position for Orifice parameter when the orifice is fully closed. If the Vector of spool travel relative to discrete spool position for Orifice parameter does not contain a positive or negative region, the extended version of the parameters extend the spool travel vector and area vector to symmetric positive and negative regions.

The orifice leakage area corresponds to the first and last elements of the extended spool travel vector. The orifice can have different leakage areas if the Vector of spool travel relative to discrete spool position for Orifice parameter has both a negative and positive region.

Assumptions and Limitations

  • The block assumes that each orifice has a symmetric opening and closing about the spool position when you set Area characteristics to Different for each flow path.

  • The block assumes that each orifice has a symmetric opening and closing scaled with the spacing of the Spool travel at each spool position index parameter when you set Area characteristics to Identical for all flow paths.

Examples

Parameterize an M-Way N-Position Valve

Parameterize an M-Way N-Position Valve

Use a data sheet to parameterize an M-Way N-Position Valve (IL).

Ports

Input

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Physical signal input port associated with the spool displacement, in m.

Conserving

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Isothermal liquid conserving port associated with port 1.

Isothermal liquid conserving ports associated with port 2 through 10, where the number of ports is equal to the Number of ports parameter.

Dependencies

To enable ports 2 through 10, set Number of ports to the number of ports you want.

Parameters

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Valve Configuration

Number of ports associated with the valve, M. You can select up to ten.

Number of spool positions, N. You can select up to ten.

Spool travel values. Each element corresponds to a different spool position index. The length of this vector must be equal to length of the Number of spool positions parameter, N. A value of 0 represents a neutral spool position.

Number of orifices. You can select up to 20.

Whether to apply identical or different parameterizations for each orifice.

Whether to parameterize each orifice linearly, with tabulated data by area, or by tabulated volumetric flow rate data according to pressure drop.

When Area characteristics is Identical for all flow paths, you can set this parameter to Linear – Area vs. spool travel or Tabulated data – Volumetric flow rate vs. pressure drop (linear with spool travel). To enable the Tabulated data – Area vs. spool travel option for this parameter, set Area characteristics to Different for each flow path.

Fractional distance between adjacent spool positions for which each orifice remains at the maximum opening area.

Dependencies

To enable this parameter, set Area characteristics to Identical for all flow paths.

Fractional distance between adjacent spool positions over which the orifice area transitions between maximum area and leakage area.

Dependencies

To enable this parameter, set Area characteristics to Identical for all flow paths.

Maximum opening area for all orifices.

Dependencies

To enable this parameter, set Area characteristics to Identical for all flow paths and Orifice parameterization to Linear – Area vs. spool travel.

Leakage area as a fraction of the value of the Maximum orifice area parameter.

Dependencies

To enable this parameter, set Orifice parameterization to Linear – Area vs. spool travel.

Cross-sectional area for all ports.

Dependencies

To enable this parameter, set either:

  • Orifice parameterization to Linear – Area vs. spool travel.

  • Area characteristics to Different for each path and Orifice parameterization to Tabulated data – Area vs. spool travel.

Correction factor that accounts for discharge losses in theoretical flows.

Dependencies

To enable this parameter, set either:

  • Orifice parameterization to Linear – Area vs. spool travel.

  • Area characteristics to Different for each path and Orifice parameterization to Tabulated data – Area vs. spool travel.

Upper Reynolds number limit for laminar flow through the orifice.

Dependencies

To enable this parameter, set either:

  • Orifice parameterization to Linear – Area vs. spool travel.

  • Area characteristics to Different for each path and Orifice parameterization to Tabulated data – Area vs. spool travel.

Continuous smoothing factor that introduces a layer of gradual change to the flow response when the valve is in near-open or near-closed positions. Set this value to a nonzero value less than one to improve the stability of your simulation in these regimes.

Dependencies

To enable this parameter, set Orifice parameterization to Linear – Area vs. spool travel.

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

Dependencies

To enable this parameter, set either:

  • Orifice parameterization to Linear – Area vs. spool travel.

  • Area characteristics to Different for each path and Orifice parameterization to Tabulated data – Area vs. spool travel.

Tabulated pressure drop values for all orifices. The elements of this vector correspond one-to-one with the Fully open volumetric flow rate vector parameter.

Dependencies

To enable this parameter, set Area characteristics to Identical for all flow paths and Orifice parameterization to Tabulated data – Volumetric flow rate vs. pressure drop (linear with spool travel).

Volumetric flow rate for a fully open orifice at a given pressure drop. The elements of this vector correspond one-to-one with the Pressure drop vector parameter.

Dependencies

To enable this parameter, set Area characteristics to Identical for all flow paths and Orifice parameterization to Tabulated data – Volumetric flow rate vs. pressure drop (linear with spool travel).

Leakage as a fraction of the Fully open volumetric flow rate vector parameter.

Dependencies

To enable this parameter, set Orifice parameterization to Tabulated data – Volumetric flow rate vs. pressure drop (linear with spool travel).

Orifice 1

This section includes only the parameters for orifice 1. The remaining orifice parameters are identical to orifice 1 except for their number and the cases mentioned in the parameter descriptions for orifice 1. To learn more, see Orifice Parameterization.

The two fluid ports connected by orifice 1. The first element is the valve port connected to the orifice A port. The second element is the valve port connected to the orifice B port. In the Simscape Results Explorer app, the variables mdot_A and mdot_B are mass flow rates into the Orifice (IL) block A and B ports, respectively. p_diff is the pressure drop from port A to port B of the orifice. In the block icon, for ports connected to a single orifice, the arrow points to the port represented by the second element of this parameter. The default values for the other orifices are:

  • Orifice 2: [4, 5]

  • Orifice 3: [2, 1]

  • Orifice 4: [3, 4]

  • Orifice 5–Orifice 20: [1, 2]

Spool positions for which orifice 1 is open. The vector must be strictly monotonically increasing with values between 1 and the value of the Number of spool positions parameter. The default values for the other orifices are:

  • Orifice 2: [1, 4]

  • Orifice 3: [3, 4]

  • Orifice 4: [3, 4]

  • Orifice 5–Orifice 20: 1

If the Spool position indices where orifice 1 is open parameter contains consecutive integers, it indicates that the orifice is open in multiple adjacent discrete spool positions. The block behavior in this case depends on the Orifice parameterization parameter:

  • If Orifice parameterization is Linear – Area vs. spool travel or Tabulated data – Volumetric flow rate vs. pressure drop (linear with spool travel), the block maintains the value of the Maximum orifice area parameter or the Fully open volumetric flow rate vector parameter across the multiple adjacent discrete spool positions where the orifice is open.

  • If Orifice parameterization is Tabulated data – Area vs. spool travel, the element in the Vector of spool travel relative to discrete spool position for orifice 1 parameter equal to 0 corresponds to the smallest-valued discrete spool position of the adjacent positions.

Spool travel across which the orifice maintains the maximum opening area. The center of this spool travel distance is at the value of the Spool position with open orifice 1 parameter.

Dependencies

To enable this parameter, set Area characteristics to Different for each flow path and Orifice parameterization to Linear – Area vs. spool travel or Tabulated data – Volumetric flow rate vs. pressure drop (linear with spool travel).

Spool travel across which the orifice transitions from fully open to fully closed.

Dependencies

To enable this parameter, set Area characteristics to Different for each flow path and Orifice parameterization to Linear – Area vs. spool travel or Tabulated data – Volumetric flow rate vs. pressure drop (linear with spool travel).

Opening area of orifice 1.

Dependencies

To enable this parameter, set Area characteristics to Different for each flow path and Orifice parameterization to Linear – Area vs. spool travel.

Vector of pressure drop values for orifice 1. These values correspond one-to-one with the Fully open volumetric flow rate vector of orifice 1 parameter.

Dependencies

To enable this parameter, set Area characteristics to Different for each flow path and Orifice parameterization to Tabulated data – Volumetric flow rate vs. pressure drop (linear with spool travel).

Volumetric flow rate when orifice 1 is fully open for a given pressure drop. These values correspond one-to-one with the Pressure drop vector of orifice 1 parameter.

Dependencies

To enable this parameter, set Area characteristics to Different for each flow path and Orifice parameterization to Tabulated data – Volumetric flow rate vs. pressure drop (linear with spool travel).

Vector of spool travel for orifice 1 that correspond to the elements in the Area vector for orifice 1 parameter. This parameter must be the same length as the Area vector for orifice 1 parameter, contain an element equal to 0, and be strictly monotonically increasing. The 0-valued element represents when the spool is in a discrete spool position index. If the Spool position indices where orifice 1 is open parameter contains multiple adjacent discrete spool positions, then the 0-valued element of the Vector of spool travel relative to discrete spool position for orifice 1 parameter corresponds to the smallest value in the sequence of adjacent positions. For example, if the Spool position indices where orifice 1 is open parameter is [1 2], [1 3 4 7], or [2 3 4 8 9], then the 0-valued element would correspond to 1, 3, or {2,8}, respectively.

If the Spool position indices where orifice 1 is open parameter is open for all spool positions, meaning the value is [1:Number of spool positions], then the 0-valued element of the Vector of spool travel relative to discrete spool position for orifice 1 parameter corresponds to the first discrete spool position. In this case, you can set the Area vector for orifice 1 parameter to the same repeating value to model a constant area orifice.

The vector can contain negative and positive elements, which represent spool travel in either direction relative to the discrete spool position for which the orifice is open. If the parameter contains only non-negative elements or only non-positive elements, then the orifice opening behaves symmetrically for negative or positive spool travel relative to the discrete position, respectively.

Dependencies

To enable this parameter, set Area characteristics to Different for each flow path and Orifice parameterization to Tabulated data – Area vs. spool travel.

Vector of orifice areas for orifice 1 that correspond to the elements in the Vector of spool travel relative to discrete spool position for orifice 1 parameter. This parameter must be the same length as the Vector of spool travel relative to discrete spool position for orifice 1 parameter. If the orifice is open in the first or last discrete spool position, then the orifice remains fully open at the maximum area when the spool travels beyond the first or last discrete spool position.

Dependencies

To enable this parameter, set Area characteristics to Different for each flow path and Orifice parameterization to Tabulated data – Area vs. spool travel.

Version History

Introduced in R2022b

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See Also