Engee documentation

Double-Acting Actuator (IL)

Double-acting linear actuator in an isothermal liquid network.

double acting actuator il

Description

The Double-Acting Actuator (IL) block models an actuator that converts the pressure drop between two chambers into piston movement. The piston movement is controlled by the differential pressure on both sides of the plate separating the chambers of the block. The limits of piston travel are modelled by one of the rigid stop models. Fluid compressibility is additionally modelled in both piston chambers.

Ports A and B represent inlets for isothermal liquid. Port C is associated with the actuator body and port R is associated with the piston, while it returns the piston velocity. The piston position is calculated internally and transferred to port p.

The direction of piston movement is set by the Mechanical orientation parameter. If the Mechanical orientation parameter is set to Pressure at A causes positive displacement of R relative to C, the piston extends at a positive differential pressure - . If the Mechanical orientation is set to Pressure at A causes negative displacement of R relative to C, the piston retracts at positive differential pressure between the chambers.

Displacement

The displacement of the piston is determined by the displacement of port R relative to port C. The value of the Mechanical orientation parameter determines the direction of piston displacement. Piston displacement is neutral (equal to 0) when the chamber volume A is equal to Dead volume.

Rigid Restrictor Model

At the extreme positions of the piston, the block models the non-linear position of the actuator. For this purpose, the block uses the same models as the block Translational Hard Stop.

At the extreme positions of the piston, a rigid limiter force is generated, whose area of effect is within the Transition region for Piston stroke or Piston initial displacement. Outside this region .

Damper

The block can simulate damping at the extreme positions of the piston. If Cylinder A end cushioning and/or Cylinder B end cushioning is checked, the block takes into account the deceleration of the piston as it approaches the maximum value of the piston stroke length defined by the Piston stroke parameter. For more information on the hydraulic cylinder damper, see the block Cylinder Cushion (IL).

Friction

When Cylinder friction effect is checked, the block accounts for the friction of the piston as it moves, with the resulting friction being a combination of Stribeck, Coulomb and viscosity effects. The block measures the pressure difference between the pressure in the chamber and the ambient pressure. For more information on the friction model and its limitations, see the block Cylinder Friction (IL).

Leakage

The block allows you to account for possible leaks between chambers A and B. If the fluid in both chambers is the same (the Same fluid on both sides and Internal leakage checkboxes are selected), Poiseuille flow is modelled between the piston and cylinder. For more information on leakage modelling, see Laminar Leakage (IL).

Where.

  • - kinematic viscosity of the fluid;

  • - piston length, p - ;

  • - pressure in port A;

  • - port pressure B;

  • - cylinder diameter, which can be written as , where is the value of the Piston-cylinder clearance parameter;

  • - piston diameter, which can be calculated as , where is the average value of the parameters Piston cross-sectional area in chamber A and Piston cross-sectional area in chamber B.

Numerical smoothing of area and pressure values

The computational robustness of the simulation is optionally controlled by the Smoothing factor parameter. If the Smoothing factor is not zero, the orifice area of dampers A and B and the pressure range of the check valve are smoothed. The orifice area changes smoothly between Leakage area between plunger and cushion sleeve and Cushion plunger cross-sectional area. The valve pressure varies smoothly between Check valve cracking pressure differential and Check valve maximum pressure differential.

Block diagram

The Double-Acting Actuator (IL) block consists of four isothermal liquid library blocks and two Mechanics library blocks:

The structure diagram of the actuator is shown in the schematic diagram.

double acting actuator il 1

Saving the pulse

The conservation of momentum equation for the actuator is as follows:

where

  • - is the force exerted by the fluid on the transducer surface. This value does not take into account the forces from the subcomponents of the unit: rigid restrictor (Translational Hard Stop), cylinder damper Cylinder Cushion (IL), cylinder friction Cylinder Friction (IL). For the contribution of these forces to the converter surface, refer to the documentation pages for these subcomponents;

  • depends on the value of the Mechanical orientation parameter:

    • If the Mechanical orientation parameter is set to Pressure at A causes positive displacement of R relative to C, then ;

    • If the Mechanical orientation parameter is set to Pressure at A causes negative displacement of R relative to C, then ;

  • - the cross-sectional area of the stem bore, which can be calculated as ;

  • - value of the parameter Piston cross-sectional area in chamber A;

  • - the value of Piston cross-sectional area in chamber B;

  • - pressure inside chamber A;

  • - pressure inside chamber B;

  • - ambient pressure.

Ports

Conserving

# A — inlet for fluid flow into the chamber A
isothermal liquid

Details

isothermal liquid port corresponding to the inlet to chamber A.

Program usage name

port_a

# B — inlet for fluid flow into the chamber B
isothermal liquid

Details

isothermal liquid port corresponding to the inlet to chamber B.

Program usage name

port_b

# R — actuator piston
translational mechanics

Details

A mechanical progressive port corresponding to the actuator piston.

Program usage name

rod_flange

# C — drive housing
translational mechanics

Details

Mechanical progressive port corresponding to the actuator housing.

Program usage name

case_flange

Output

# p — piston position
scalar

Details

Piston position in m.

Data types

Float64.

Complex numbers support

No

Parameters

Actuator

# Same fluid on both sides — whether the same fluid is modelled in both chambers of the unit

Details

Whether the same fluid is modelled on both sides of the block. If the checkbox is selected, the fluid properties are propagated through the block. If unchecked, the chambers in the block are connected to isolated networks of fluids with different properties.

Default value

true (switched on)

Program usage name

same_properties

Evaluatable

No

# Mechanical orientation — piston travel direction
Pressure at A causes positive displacement of R relative to C | Pressure at A causes negative displacement of R relative to C

Details

Defines the direction of piston movement. Options for selection:

  • `Pressure at A causes positive displacement of R relative to C' - piston movement is positive if the fluid volume in port A increases. This corresponds to the movement of the rod out of the cylinder.

  • Pressure at A causes negative displacement of R relative to C - piston movement is negative if the volume of fluid in port A increases. This corresponds to movement of the rod inside the cylinder.

Values

Pressure at A causes positive displacement of R relative to C | Pressure at A causes negative displacement of R relative to C

Default value

Pressure at A causes positive displacement of R relative to C

Program usage name

orientation

Evaluatable

No

# Piston cross-sectional area in chamber A — cross-sectional area of the chamber piston rod A
m^2 | cm^2 | ft^2 | in^2 | km^2 | mi^2 | mm^2 | um^2 | yd^2

Details

Cross-sectional area of the piston rod on the chamber side A.

Values

m^2 | cm^2 | ft^2 | in^2 | km^2 | mi^2 | mm^2 | um^2 | yd^2

Default value

0.01 m^2

Program usage name

piston_area_a

Evaluatable

Yes

# Piston cross-sectional area in chamber B — cross-sectional area of the chamber piston rod B
m^2 | cm^2 | ft^2 | in^2 | km^2 | mi^2 | mm^2 | um^2 | yd^2

Details

Cross-sectional area of the piston rod on the chamber side B.

Values

m^2 | cm^2 | ft^2 | in^2 | km^2 | mi^2 | mm^2 | um^2 | yd^2

Default value

0.01 m^2

Program usage name

piston_area_b

Evaluatable

Yes

# Piston stroke — piston stroke
m | cm | ft | in | km | mi | mm | um | yd

Details

Maximum possible piston travel.

Values

m | cm | ft | in | km | mi | mm | um | yd

Default value

0.1 m

Program usage name

stroke

Evaluatable

Yes

# Dead volume in chamber A — volume of liquid in chamber A, at which piston movement is equal to 0
l | gal | igal | m^3 | cm^3 | ft^3 | in^3 | km^3 | mi^3 | mm^3 | um^3 | yd^3 | N*m/Pa | N*m/bar | lbf*ft/psi | ft*lbf/psi

Details

Volume of liquid in chamber A at piston movement value 0. This fluid volume corresponds to the position of the piston at which it is up against the actuator end cap.

Values

l | gal | igal | m^3 | cm^3 | ft^3 | in^3 | km^3 | mi^3 | mm^3 | um^3 | yd^3 | N*m/Pa | N*m/bar | lbf*ft/psi | ft*lbf/psi

Default value

1e-05 m^3

Program usage name

dead_volume_a

Evaluatable

Yes

# Dead volume in chamber B — volume of liquid in the chamber B, at which the piston movement is equal to 0
l | gal | igal | m^3 | cm^3 | ft^3 | in^3 | km^3 | mi^3 | mm^3 | um^3 | yd^3 | N*m/Pa | N*m/bar | lbf*ft/psi | ft*lbf/psi

Details

Volume of liquid in chamber B at piston movement value `0'. This fluid volume corresponds to the position of the piston at which it is up against the actuator end cap.

Values

l | gal | igal | m^3 | cm^3 | ft^3 | in^3 | km^3 | mi^3 | mm^3 | um^3 | yd^3 | N*m/Pa | N*m/bar | lbf*ft/psi | ft*lbf/psi

Default value

1e-05 m^3

Program usage name

dead_volume_b

Evaluatable

Yes

# Environment pressure specification — method of setting the ambient pressure
Atmospheric pressure | Specified pressure

Details

Method of setting the ambient pressure. The Atmospheric pressure option sets the ambient pressure to 0.101325 MPa.

Values

Atmospheric pressure | Specified pressure

Default value

Atmospheric pressure

Program usage name

pressure_type

Evaluatable

No

# Environment pressure — ambient pressure
Pa | GPa | MPa | atm | bar | kPa | ksi | psi | uPa | kbar

Details

User-defined ambient pressure.

Dependencies

To use this parameter, set Environment pressure specification to Specified pressure.

Values

Pa | GPa | MPa | atm | bar | kPa | ksi | psi | uPa | kbar

Default value

0.101325 MPa

Program usage name

p_specified

Evaluatable

Yes

Hard Stop

# Hard stop model — selecting the model of the hard stop
Stiffness and damping applied smoothly through transition region, damped rebound | Full stiffness and damping applied at bounds, undamped rebound | Full stiffness and damping applied at bounds, damped rebound

Details

Selects the model for the force acting on the piston when it is at the end positions. See block for more information Translational Hard Stop

Values

Stiffness and damping applied smoothly through transition region, damped rebound | Full stiffness and damping applied at bounds, undamped rebound | Full stiffness and damping applied at bounds, damped rebound

Default value

Stiffness and damping applied smoothly through transition region, damped rebound

Program usage name

hardstop_model

Evaluatable

No

# Hard stop stiffness coefficient — stiffness factor
N/m | lbf/ft | lbf/in

Details

Piston stiffness coefficient.

Values

N/m | lbf/ft | lbf/in

Default value

1e10 N/m

Program usage name

k_hard_stop

Evaluatable

Yes

# Hard stop damping coefficient — damping factor
kg/s | N*s/m | N/(m/s) | lbf/(ft/s) | lbf/(in/s)

Details

Piston damping factor.

Values

kg/s | N*s/m | N/(m/s) | lbf/(ft/s) | lbf/(in/s)

Default value

150.0 N*s/m

Program usage name

C_hard_stop

Evaluatable

Yes

# Transition region — range of action of the rigid stop model
m | cm | ft | in | km | mi | mm | um | yd

Details

The operating range of the hard stop model. Outside this range, the Hard stop model does not apply to the extreme piston positions and no additional force is applied to the piston from the stop.

Dependencies

To use this parameter, set the Hard stop model to `Stiffness and damping applied smoothly through transition region, damped rebound'.

Values

m | cm | ft | in | km | mi | mm | um | yd

Default value

0.1 mm

Program usage name

transition_region

Evaluatable

Yes

Cushion A

# Cylinder A end cushioning — option to simulate piston braking due to damper action

Details

Whether the deceleration of the piston at its extreme positions is taken into account. For more information, see the block see the block Cylinder Cushion (IL).

Default value

false (switched off)

Program usage name

enable_cylinder_cushion_a

Evaluatable

No

# Cushion plunger cross-sectional area — cross-sectional area of the damping plug
m^2 | cm^2 | ft^2 | in^2 | km^2 | mi^2 | mm^2 | um^2 | yd^2

Details

Cross-sectional area of the damping plug.

Dependencies

To use this parameter, select the Cylinder A end cushioning checkbox.

Values

m^2 | cm^2 | ft^2 | in^2 | km^2 | mi^2 | mm^2 | um^2 | yd^2

Default value

0.0001 m^2

Program usage name

plunger_area_a

Evaluatable

Yes

# Cushion plunger length — damping plug length
m | cm | ft | in | km | mi | mm | um | yd

Details

Length of the damping plug.

Dependencies

To use this parameter, select the Cylinder A end cushioning checkbox.

Values

m | cm | ft | in | km | mi | mm | um | yd

Default value

0.001 m

Program usage name

plunger_length_a

Evaluatable

Yes

# Cushion orifice area — area of the opening between the damper chambers
m^2 | cm^2 | ft^2 | in^2 | km^2 | mi^2 | mm^2 | um^2 | yd^2

Details

The area of the opening between the damper chambers.

Dependencies

To use this parameter, select the Cylinder A end cushioning checkbox.

Values

m^2 | cm^2 | ft^2 | in^2 | km^2 | mi^2 | mm^2 | um^2 | yd^2

Default value

1e-06 m^2

Program usage name

cushioning_valve_area_a

Evaluatable

Yes

# Leakage area between plunger and cushion sleeve — clearance area between damper plug and bushing
m^2 | cm^2 | ft^2 | in^2 | km^2 | mi^2 | mm^2 | um^2 | yd^2

Details

The clearance area between the damper plunger and the sleeve. The parameter maintains the computational stability of the simulation by ensuring flow continuity.

Dependencies

To use this parameter, select the Cylinder A end cushioning checkbox.

Values

m^2 | cm^2 | ft^2 | in^2 | km^2 | mi^2 | mm^2 | um^2 | yd^2

Default value

1e-07 m^2

Program usage name

plunger_leakage_area_a

Evaluatable

Yes

# Check valve cracking pressure differential — differential pressure at which the check valve starts to open
Pa | GPa | MPa | atm | bar | kPa | ksi | psi | uPa | kbar

Details

The pressure above which the damper actuates. When the pressure difference between port A and meets or exceeds this parameter, the damper check valve starts to open.

Dependencies

To use this parameter, select the Cylinder A end cushioning checkbox.

Values

Pa | GPa | MPa | atm | bar | kPa | ksi | psi | uPa | kbar

Default value

0.01 MPa

Program usage name

delta_p_crack_a

Evaluatable

Yes

# Check valve maximum pressure differential — pressure drop required to fully open the check valve
Pa | GPa | MPa | atm | bar | kPa | ksi | psi | uPa | kbar

Details

Maximum differential pressure of the damper check valve. This parameter sets the upper pressure limit so that the system pressure remains realistic.

Dependencies

To use this parameter, select the Cylinder A end cushioning checkbox.

Values

Pa | GPa | MPa | atm | bar | kPa | ksi | psi | uPa | kbar

Default value

0.1 MPa

Program usage name

delta_p_max_a

Evaluatable

Yes

# Check valve maximum area — area of fully open check valve
m^2 | cm^2 | ft^2 | in^2 | km^2 | mi^2 | mm^2 | um^2 | yd^2

Details

The cross-sectional area of the check valve orifice in the fully open position.

Dependencies

To use this parameter, select the Cylinder A end cushioning checkbox.

Values

m^2 | cm^2 | ft^2 | in^2 | km^2 | mi^2 | mm^2 | um^2 | yd^2

Default value

0.0001 m^2

Program usage name

check_valve_max_area_a

Evaluatable

Yes

# Check valve leakage area — leakage area with fully closed check valve
m^2 | cm^2 | ft^2 | in^2 | km^2 | mi^2 | mm^2 | um^2 | yd^2

Details

Total possible leakage area with the check valve fully closed. Any area smaller than this value increases smoothly to the specified leakage area. This value contributes to computational stability by maintaining flow continuity.

Dependencies

To use this parameter, select the Cylinder A end cushioning checkbox.

Values

m^2 | cm^2 | ft^2 | in^2 | km^2 | mi^2 | mm^2 | um^2 | yd^2

Default value

1e-10 m^2

Program usage name

check_valve_leakage_area_a

Evaluatable

Yes

# Smoothing factor — numerical smoothing factor

Details

Continuous smoothing factor that provides a smooth opening by correcting the valve characteristic in the nearly open and nearly closed positions. Set a non-zero value less than one to increase the stability of the simulation.

Dependencies

To use this parameter, select the Cylinder A end cushioning checkbox.

Default value

0.01

Program usage name

smoothing_factor_a

Evaluatable

Yes

Cushion B

# Cylinder B end cushioning — option to simulate piston braking due to damper action

Details

Whether the deceleration of the piston at its extreme positions is taken into account. For more information, see the block see the block Cylinder Cushion (IL).

Default value

false (switched off)

Program usage name

enable_cylinder_cushion_b

Evaluatable

No

# Cushion plunger cross-sectional area — cross-sectional area of the damping plug
m^2 | cm^2 | ft^2 | in^2 | km^2 | mi^2 | mm^2 | um^2 | yd^2

Details

Cross-sectional area of the damping plug.

Dependencies

To use this parameter, select the Cylinder B end cushioning checkbox.

Values

m^2 | cm^2 | ft^2 | in^2 | km^2 | mi^2 | mm^2 | um^2 | yd^2

Default value

0.0001 m^2

Program usage name

plunger_area_b

Evaluatable

Yes

# Cushion plunger length — damping plug length
m | cm | ft | in | km | mi | mm | um | yd

Details

Length of the damping plug.

Dependencies

To use this parameter, select the Cylinder B end cushioning checkbox.

Values

m | cm | ft | in | km | mi | mm | um | yd

Default value

0.001 m

Program usage name

plunger_length_b

Evaluatable

Yes

# Cushion orifice area — area of the opening between the damper chambers
m^2 | cm^2 | ft^2 | in^2 | km^2 | mi^2 | mm^2 | um^2 | yd^2

Details

The area of the opening between the damper chambers.

Dependencies

To use this parameter, select the Cylinder B end cushioning checkbox.

Values

m^2 | cm^2 | ft^2 | in^2 | km^2 | mi^2 | mm^2 | um^2 | yd^2

Default value

1e-06 m^2

Program usage name

cushioning_valve_area_b

Evaluatable

Yes

# Leakage area between plunger and cushion sleeve — clearance area between damper plug and bushing
m^2 | cm^2 | ft^2 | in^2 | km^2 | mi^2 | mm^2 | um^2 | yd^2

Details

The clearance area between the damper plunger and the sleeve. The parameter maintains the computational stability of the simulation by ensuring flow continuity.

Dependencies

To use this parameter, select the Cylinder B end cushioning checkbox.

Values

m^2 | cm^2 | ft^2 | in^2 | km^2 | mi^2 | mm^2 | um^2 | yd^2

Default value

1e-07 m^2

Program usage name

plunger_leakage_area_b

Evaluatable

Yes

# Check valve cracking pressure differential — differential pressure at which the check valve starts to open
Pa | GPa | MPa | atm | bar | kPa | ksi | psi | uPa | kbar

Details

The pressure above which the damper actuates. When the pressure difference between port B and meets or exceeds the value of this parameter, the damper check valve starts to open.

Dependencies

To use this parameter, select the Cylinder B end cushioning checkbox.

Values

Pa | GPa | MPa | atm | bar | kPa | ksi | psi | uPa | kbar

Default value

0.01 MPa

Program usage name

delta_p_crack_b

Evaluatable

Yes

# Check valve maximum pressure differential — pressure drop required to fully open the check valve
Pa | GPa | MPa | atm | bar | kPa | ksi | psi | uPa | kbar

Details

Maximum differential pressure of the damper check valve. This parameter sets the upper pressure limit so that the system pressure remains realistic.

Dependencies

To use this parameter, select the Cylinder B end cushioning checkbox.

Values

Pa | GPa | MPa | atm | bar | kPa | ksi | psi | uPa | kbar

Default value

0.1 MPa

Program usage name

delta_p_max_b

Evaluatable

Yes

# Check valve maximum area — area of fully open check valve
m^2 | cm^2 | ft^2 | in^2 | km^2 | mi^2 | mm^2 | um^2 | yd^2

Details

The cross-sectional area of the check valve orifice in the fully open position.

Dependencies

To use this parameter, select the Cylinder B end cushioning checkbox.

Values

m^2 | cm^2 | ft^2 | in^2 | km^2 | mi^2 | mm^2 | um^2 | yd^2

Default value

0.0001 m^2

Program usage name

check_valve_max_area_b

Evaluatable

Yes

# Check valve leakage area — leakage area with fully closed check valve
m^2 | cm^2 | ft^2 | in^2 | km^2 | mi^2 | mm^2 | um^2 | yd^2

Details

Total possible leakage area with the check valve fully closed. Any area smaller than this value increases smoothly to the specified leakage area. This value contributes to computational stability by maintaining flow continuity.

Dependencies

To use this parameter, select the Cylinder B end cushioning checkbox.

Values

m^2 | cm^2 | ft^2 | in^2 | km^2 | mi^2 | mm^2 | um^2 | yd^2

Default value

1e-10 m^2

Program usage name

check_valve_leakage_area_b

Evaluatable

Yes

# Smoothing factor — numerical smoothing factor

Details

Continuous smoothing factor that provides a smooth opening by correcting the valve characteristic in the nearly open and nearly closed positions. Set a non-zero value less than one to increase the stability of the simulation.

Dependencies

To use this parameter, select the Cylinder B end cushioning checkbox.

Default value

0.01

Program usage name

smoothing_factor_b

Evaluatable

Yes

Friction

# Cylinder friction effect — option for modelling friction during piston movement

Details

Whether the friction of the piston during movement is taken into account. The block friction force is made up of the Stribeck force, Coulomb force and viscosity. For more information, see block Cylinder Friction (IL).

Default value

false (switched off)

Program usage name

enable_friction

Evaluatable

No

# Breakaway to Coulomb friction force ratio — the ratio of the detachment force to the Coulomb friction force

Details

The ratio of the detachment force to the Coulomb friction force.

Dependencies

To use this parameter, select the Cylinder friction effect checkbox.

Default value

1.2

Program usage name

Coulomb_breakaway_ratio

Evaluatable

Yes

# Breakaway friction velocity — friction threshold
fpm | fps | kph | mph | m/s | cm/s | ft/s | in/s | km/s | mi/s | mm/s

Details

The threshold value of velocity at which anti-friction motion begins.

Dependencies

To use this parameter, select the Cylinder friction effect checkbox.

Values

fpm | fps | kph | mph | m/s | cm/s | ft/s | in/s | km/s | mi/s | mm/s

Default value

0.1 m/s

Program usage name

v_breakaway

Evaluatable

Yes

# Preload force — initial force in the cylinder during seal assembly, N
N | kN | lb | mN | dyn | lbf

Details

Initial force in the cylinder due to the seal assembly. The unit uses this parameter to calculate the Coulomb friction force.

Dependencies

To use this parameter, select the Cylinder friction effect checkbox.

Values

N | kN | lb | mN | dyn | lbf

Default value

20.0 N

Program usage name

F_preload

Evaluatable

Yes

# Coulomb friction force coefficient — Coulomb friction force coefficient
m^2 | cm^2 | ft^2 | in^2 | km^2 | mi^2 | mm^2 | um^2 | yd^2 | N/Pa

Details

Coulomb friction force coefficient.

Dependencies

To use this parameter, select the Cylinder friction effect checkbox.

Values

m^2 | cm^2 | ft^2 | in^2 | km^2 | mi^2 | mm^2 | um^2 | yd^2 | N/Pa

Default value

1e-06 N/Pa

Program usage name

Coulomb_coefficient

Evaluatable

Yes

# Viscous friction coefficient — viscous friction coefficient
kg/s | N*s/m | N/(m/s) | lbf/(ft/s) | lbf/(in/s)

Details

Coefficient of viscous friction.

Dependencies

To use this parameter, select the Cylinder friction effect checkbox.

Values

kg/s | N*s/m | N/(m/s) | lbf/(ft/s) | lbf/(in/s)

Default value

100.0 N*s/m

Program usage name

viscous_coefficient

Evaluatable

Yes

Leakage

# Internal leakage — annular leakage modelling option

Details

Whether leakage through the annular gap between actuator chamber and piston is taken into account under reference ambient conditions. The flow through the gap is laminar. For more information, see block Laminar Leakage (IL).

Dependencies

To use this parameter, select the Same fluid on both sides checkbox.

Default value

false (switched off)

Program usage name

enable_leakage

Evaluatable

No

# Piston-cylinder clearance — radial clearance
m | cm | ft | in | km | mi | mm | um | yd

Details

The radial distance between the piston rod and the cylinder body.

Dependencies

To use this parameter, select the Same fluid on both sides and Internal leakage checkboxes.

Values

m | cm | ft | in | km | mi | mm | um | yd

Default value

0.0001 m

Program usage name

clearance

Evaluatable

Yes

# Piston head length — piston head length
m | cm | ft | in | km | mi | mm | um | yd

Details

Length of the piston head.

Dependencies

To use this parameter, select the Same fluid on both sides and Internal leakage checkboxes.

Values

m | cm | ft | in | km | mi | mm | um | yd

Default value

0.01 m

Program usage name

piston_length

Evaluatable

Yes

Initial Conditions

# Initial piston displacement from chamber A cap — initial position of the piston relative to the chamber cover A
m | cm | ft | in | km | mi | mm | um | yd

Details

Piston position relative to the chamber lid A at the beginning of the simulation.

Values

m | cm | ft | in | km | mi | mm | um | yd

Default value

0.0 m

Program usage name

offset

Evaluatable

Yes

# Fluid dynamic compressibility — fluid compressibility modelling option

Details

Account for changes in fluid density due to fluid compressibility. When Fluid dynamic compressibility is checked, changes due to the mass flow rate of the fluid in the block are calculated in addition to density changes due to pressure changes. In the isothermal liquid library, all blocks calculate density as a function of pressure.

Default value

true (switched on)

Program usage name

dynamic_compressibility

Evaluatable

No

# Initial liquid pressure in chamber A — initial fluid pressure for compressible liquids in the chamber A
Pa | GPa | MPa | atm | bar | kPa | ksi | psi | uPa | kbar

Details

Initial fluid pressure for compressible liquids in chamber A.

Dependencies

To use this parameter, select the Fluid dynamic compressibility checkbox.

Values

Pa | GPa | MPa | atm | bar | kPa | ksi | psi | uPa | kbar

Default value

0.101325 MPa

Program usage name

p_start_a

Evaluatable

Yes

# Initial liquid pressure in chamber B — initial fluid pressure for compressible liquids in the chamber B
Pa | GPa | MPa | atm | bar | kPa | ksi | psi | uPa | kbar

Details

Initial fluid pressure for compressible liquids in chamber B.

Dependencies

To use this parameter, select the Fluid dynamic compressibility checkbox.

Values

Pa | GPa | MPa | atm | bar | kPa | ksi | psi | uPa | kbar

Default value

0.101325 MPa

Program usage name

p_start_b

Evaluatable

Yes