Pressure Source (IL)

Generate specified pressure differential in isothermal liquid network

Since R2020a

Libraries:
Simscape / Foundation Library / Isothermal Liquid / Sources

Description

The Pressure Source (IL) block represents an ideal mechanical energy source in an isothermal liquid network. The source can maintain specified pressure differential across its ports regardless of the mass flow rate through the source. There is no flow resistance and no heat exchange with the environment.

Ports A and B represent the source inlet and outlet. The input physical signal at port P specifies the pressure differential. Alternatively, you can specify a constant pressure differential as a block parameter. A positive pressure differential causes the pressure at port B to be greater than the pressure at port A.

The block calculates the work performed on the fluid and includes the results in the simulation data log for information purposes:

$W_{m e c h} = \dot{m} \frac{p_{B} - p_{A}}{\bar{ρ}}$

$\bar{ρ} = \frac{ρ_{A} + ρ_{B}}{2}$

where:

W_mech is the mechanical work performed by the source.
$\dot{m}$ is the mass flow rate generated by the source.
p_A and p_B are pressures at ports A and B, respectively.
$\bar{ρ}$ is the average fluid mixture density.
ρ_A and ρ_B are fluid mixture density values at ports A and B, respectively. Equations used to compute the fluid mixture density depend on the selected isothermal liquid model. For detailed information, see Isothermal Liquid Modeling Options.

For information on viewing logged simulation data, see Data Logging.

Assumptions and Limitations

There are no losses due to friction.
There is no heat exchange with the environment.

Examples

Hydraulic Actuator with Analog Position Controller

How the Foundation library can be used to model systems that span electrical, mechanical and isothermal liquid domains. In the model, a hydraulic system implemented in the isothermal liquid domain controls the mechanical load position in response to a voltage reference demand. If the reference demand is zero, then the hydraulic actuator (and load) displacement is zero, and if the reference is +5 volts, then the displacement is 100 mm.

Open Model

Ports

Input

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P — Pressure differential control signal, Pa
physical signal

Input physical signal that specifies the pressure differential across the source.

Dependencies

This port is visible if you set the Source type parameter to Controlled.

Conserving

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A — Source inlet
isothermal liquid

Isothermal liquid conserving port. A positive pressure differential causes the pressure at port B to be greater than the pressure at port A.

B — Source outlet
isothermal liquid

Isothermal liquid conserving port. A positive pressure differential causes the pressure at port B to be greater than the pressure at port A.

Parameters

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Source type — Select whether pressure differential can change during simulation
`Controlled` (default) | `Constant`

Select whether the pressure differential generated by the source can change during simulation:

Controlled — The pressure differential is variable, controlled by an input physical signal. Selecting this option exposes the input port P.
Constant — The pressure differential is constant during simulation, specified by a block parameter. Selecting this option enables the Pressure differential parameter.

Pressure differential — Constant pressure differential across the source
`0 MPa` (default) | scalar

Desired pressure differential across the source.

Dependencies

Enabled when you set the Source type parameter to Constant.

Extended Capabilities

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

Version History

Introduced in R2020a

Pressure Source (IL)