Double-Acting Actuator (G)

Two-way linear actuator in the gas network.

blockType: EngeeFluids.Gas.Actuators.TranslationalDoubleActing

Path in the library:

/Physical Modeling/Fluids/Gas/Actuators/Double-Acting Actuator (G)

Description

Block Double-Acting Actuator (G) It simulates a drive that converts the pressure difference between two chambers into a piston movement. The movement of the piston is controlled by the pressure drop on both sides of the plate separating the chambers of the block. The stroke limits of the piston are modeled by one of the rigid stop models.

The figure shows the main components of the drive. Ports A and B are gas inputs. Port C is associated with the drive housing, port R is associated with the piston, and it returns the speed of the piston. The position of the piston is calculated inside the system and transmitted to port p.

Ports HA and HB represent the thermal interfaces between each gas chamber and the surrounding environment. The moving piston is adiabatic.

double acting actuator g 1

Moving

The movement of the piston is determined by the displacement of port R relative to port C. Parameter Value Mechanical orientation determines the direction of displacement of the piston. The movement of the piston is neutral (equal to 0), when the volume of the camera A is Dead volume in chamber A.

The direction of movement of the piston depends on the parameter Mechanical orientation. If the value is set to Pressure at A causes positive displacement of R relative to C, the displacement of the piston will be positive with respect to the drive housing when the gauge pressure at port A is positive. The direction of movement is reversed if the value is set to Pressure at A causes negative displacement of R relative to C.

The hard limiter model

A set of rigid stops limits the range of motion of the piston. This block uses the implementation of the block Translational Hard Stop in which rigid stops are considered as spring-damping systems. The spring stiffness coefficient determines the restoring component of the contact force of the rigid stop, and the damping coefficient determines the scattering component.

Rigid stops are located at the distal ends of the piston stroke. If the mechanical orientation is positive, then the lower rigid stop is in position , and the upper rigid stop is in position . If the mechanical orientation is negative, then the lower rigid stop is in position , and the upper rigid stop is in position .

Block diagram

Block Double-Acting Actuator (G) it consists of one library block Gas and two library blocks Mechanics:

The structural diagram of the drive is shown in the diagram.

double acting actuator g 2

Ports

Conserving

# A — inlet for gas flow into the chamber A
gas

Details

Port corresponding to the gas inlet to the A chamber.

Program usage name

port_a

# B — inlet for gas flow into the chamber B
gas

Details

Port corresponding to the gas 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 — actuator housing
translational mechanics

Details

Mechanical progressive port corresponding to the actuator housing.

Program usage name

case_flange

# HA — heat associated with the chamber A
`heat

Details

Thermal non-directional port associated with chamber A.

Program usage name

thermal_port_a

# HB — heat associated with the chamber B
`heat

Details

Thermal non-directional port associated with chamber B.

Program usage name

thermal_port_b

Output

# p — piston position
scalar

Details

Piston position in m.

Data types	`Float64`.
Complex numbers support	No

Parameters

Actuator

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

Details

Whether the same fluid is simulated on both sides of the block. If the option is checked, then the properties of the liquid are distributed through the block. If unchecked, the chambers of the unit are connected to isolated networks of liquids with different properties.

Default value	`true (switched on)`
Program usage name	`same_properties`
Evaluatable	No

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

Details

Determines the direction of movement of the piston. Options to choose from:

Pressure at A causes positive displacement of R relative to C — the movement of the piston is positive if the volume of gas 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 displacement is negative if the volume of gas in port A increases. This corresponds to the 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 — the cross-sectional area of the piston rod of the chamber A
m^2 | um^2 | mm^2 | cm^2 | km^2 | in^2 | ft^2 | yd^2 | mi^2 | ha | ac

Details

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

Units	`m^2` \| `um^2` \| `mm^2` \| `cm^2` \| `km^2` \| `in^2` \| `ft^2` \| `yd^2` \| `mi^2` \| `ha` \| `ac`
Default value	`0.01 m^2`
Program usage name	`piston_area_a`
Evaluatable	Yes

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

Details

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

Units	`m^2` \| `um^2` \| `mm^2` \| `cm^2` \| `km^2` \| `in^2` \| `ft^2` \| `yd^2` \| `mi^2` \| `ha` \| `ac`
Default value	`0.01 m^2`
Program usage name	`piston_area_b`
Evaluatable	Yes

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

Details

The maximum possible displacement of the piston.

Units	`m` \| `um` \| `mm` \| `cm` \| `km` \| `in` \| `ft` \| `yd` \| `mi` \| `nmi`
Default value	`0.1 m`
Program usage name	`stroke`
Evaluatable	Yes

# Dead volume in chamber A — the volume of gas in the chamber A, at which the movement of the piston is 0
m^3 | um^3 | mm^3 | cm^3 | km^3 | ml | l | gal | igal | in^3 | ft^3 | yd^3 | mi^3

Details

The volume of gas in the chamber A at the value of the piston displacement 0. This volume of gas corresponds to the position of the piston, at which it is located at the top in relation to the end cap of the actuator.

Units	`m^3` \| `um^3` \| `mm^3` \| `cm^3` \| `km^3` \| `ml` \| `l` \| `gal` \| `igal` \| `in^3` \| `ft^3` \| `yd^3` \| `mi^3`
Default value	`1e-05 m^3`
Program usage name	`dead_volume_a`
Evaluatable	Yes

# Dead volume in chamber B — the volume of gas in the chamber B at which the piston movement is 0
m^3 | um^3 | mm^3 | cm^3 | km^3 | ml | l | gal | igal | in^3 | ft^3 | yd^3 | mi^3

Details

The volume of gas in the chamber B at the value of the piston displacement 0. This volume of gas corresponds to the position of the piston, at which it is located at the top in relation to the end cap of the actuator.

Units	`m^3` \| `um^3` \| `mm^3` \| `cm^3` \| `km^3` \| `ml` \| `l` \| `gal` \| `igal` \| `in^3` \| `ft^3` \| `yd^3` \| `mi^3`
Default value	`1e-05 m^3`
Program usage name	`dead_volume_b`
Evaluatable	Yes

# Cross-sectional area at port A — port cross-sectional area A
m^2 | um^2 | mm^2 | cm^2 | km^2 | in^2 | ft^2 | yd^2 | mi^2 | ha | ac

Details

The cross-sectional area at the entrance.

Units	`m^2` \| `um^2` \| `mm^2` \| `cm^2` \| `km^2` \| `in^2` \| `ft^2` \| `yd^2` \| `mi^2` \| `ha` \| `ac`
Default value	`0.01 m^2`
Program usage name	`port_a_area`
Evaluatable	Yes

# Cross-sectional area at port B — port cross-sectional area B
m^2 | um^2 | mm^2 | cm^2 | km^2 | in^2 | ft^2 | yd^2 | mi^2 | ha | ac

Details

The cross-sectional area at the outlet.

Units	`m^2` \| `um^2` \| `mm^2` \| `cm^2` \| `km^2` \| `in^2` \| `ft^2` \| `yd^2` \| `mi^2` \| `ha` \| `ac`
Default value	`0.01 m^2`
Program usage name	`port_b_area`
Evaluatable	Yes

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

Details

The method of setting the ambient pressure. Option Atmospheric pressure sets the ambient pressure equal 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 | uPa | hPa | kPa | MPa | GPa | kgf/m^2 | kgf/cm^2 | kgf/mm^2 | mbar | bar | kbar | atm | ksi | psi | mmHg | inHg

Details

User-defined ambient pressure.

Dependencies

To use this parameter, set for the parameter Environment pressure specification meaning Specified pressure.

Units	`Pa` \| `uPa` \| `hPa` \| `kPa` \| `MPa` \| `GPa` \| `kgf/m^2` \| `kgf/cm^2` \| `kgf/mm^2` \| `mbar` \| `bar` \| `kbar` \| `atm` \| `ksi` \| `psi` \| `mmHg` \| `inHg`
Default value	`0.101325 MPa`
Program usage name	`p_specified`
Evaluatable	Yes

Hard Stop

# Hard-stop model — choosing a rigid stop model
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 | Based on coefficient of restitution

Details

Selecting a model for the force acting on the piston when it is in extreme positions. For more information, see the block 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` \| `Based on coefficient of restitution`
Default value	`Stiffness and damping applied smoothly through transition region, damped rebound`
Program usage name	`hardstop_model`
Evaluatable	No

# Hard-stop stiffness coefficient — stiffness coefficient
N/m | mN/m | kN/m | MN/m | GN/m | kgf/m | lbf/ft | lbf/in

Details

The coefficient of piston stiffness.

Units	`N/m` \| `mN/m` \| `kN/m` \| `MN/m` \| `GN/m` \| `kgf/m` \| `lbf/ft` \| `lbf/in`
Default value	`1e10 N/m`
Program usage name	`k_hard_stop`
Evaluatable	Yes

# Hard-stop damping coefficient — damping coefficient
N*s/m | kgf*s/m | lbf*s/ft | lbf*s/in

Details

Piston damping coefficient.

Units	`Ns/m` \| `kgfs/m` \| `lbfs/ft` \| `lbfs/in`
Default value	`150.0 N*s/m`
Program usage name	`C_hard_stop`
Evaluatable	Yes

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

Details

The area of operation of the rigid stop. Outside of this range for the extreme positions of the piston Hard-stop model it is not applied, and the additional force from the stop side does not act on the piston.

Dependencies

To use this parameter, set for the parameter Hard-stop model meaning Stiffness and damping applied smoothly through transition region, damped rebound.

Units	`m` \| `um` \| `mm` \| `cm` \| `km` \| `in` \| `ft` \| `yd` \| `mi` \| `nmi`
Default value	`0.1 mm`
Program usage name	`transition_region`
Evaluatable	Yes

# Coefficient of restitution — the ratio of the final and initial relative velocity between the rod and the stop after a collision

Details

The ratio of the final and initial relative velocity between the rod and the stop after the rod rebounds.

Dependencies

To use this parameter, set for the parameter Hard-stop model meaning Based on coefficient of restitution.

Default value	`0.7`
Program usage name	`restitution_coefficient`
Evaluatable	Yes

# Static contact speed threshold — threshold value of the relative velocity between the rod and the stop before the collision
m/s | mm/s | cm/s | km/s | m/hr | km/hr | in/s | ft/s | mi/s | ft/min | mi/hr | kn

Details

The threshold value of the relative velocity between the rod and the stop before the collision. If the rod hits the housing at a speed lower than the value of this parameter, they remain in contact. Otherwise, the rod bounces off. To avoid simulating static contact between the rod and the housing, set this parameter to 0.

Dependencies

To use this parameter, set for the parameter Hard-stop model meaning Based on coefficient of restitution.

Units	`m/s` \| `mm/s` \| `cm/s` \| `km/s` \| `m/hr` \| `km/hr` \| `in/s` \| `ft/s` \| `mi/s` \| `ft/min` \| `mi/hr` \| `kn`
Default value	`0.001 m/s`
Program usage name	`v_static_contact_threshold`
Evaluatable	Yes

# Static contact release force threshold — the threshold value of the force required to transition from the contact state to the free state
N | nN | uN | mN | kN | MN | GN | dyn | lbf | kgf

Details

The minimum force required to remove the rod from the static contact state.

Dependencies

To use this parameter, set for the parameter Hard-stop model meaning Based on coefficient of restitution.

Units	`N` \| `nN` \| `uN` \| `mN` \| `kN` \| `MN` \| `GN` \| `dyn` \| `lbf` \| `kgf`
Default value	`0.001 N`
Program usage name	`F_static_contact_release_threshold`
Evaluatable	Yes

Initial Conditions

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

Details

The position of the piston relative to the chamber cover A at the beginning of the simulation.

Units	`m` \| `um` \| `mm` \| `cm` \| `km` \| `in` \| `ft` \| `yd` \| `mi` \| `nmi`
Default value	`0.0 m`
Program usage name	`offset`
Evaluatable	Yes

# Initial gas pressure in chamber A — initial gas pressure in the chamber A
Pa | uPa | hPa | kPa | MPa | GPa | kgf/m^2 | kgf/cm^2 | kgf/mm^2 | mbar | bar | kbar | atm | ksi | psi | mmHg | inHg

Details

The initial gas pressure in the chamber is A.

Units	`Pa` \| `uPa` \| `hPa` \| `kPa` \| `MPa` \| `GPa` \| `kgf/m^2` \| `kgf/cm^2` \| `kgf/mm^2` \| `mbar` \| `bar` \| `kbar` \| `atm` \| `ksi` \| `psi` \| `mmHg` \| `inHg`
Default value	`0.101325 MPa`
Program usage name	`p_start_a`
Evaluatable	Yes

# Initial gas pressure in chamber B — initial gas pressure in the chamber B
Pa | uPa | hPa | kPa | MPa | GPa | kgf/m^2 | kgf/cm^2 | kgf/mm^2 | mbar | bar | kbar | atm | ksi | psi | mmHg | inHg

Details

The initial gas pressure in the chamber is B.

Units	`Pa` \| `uPa` \| `hPa` \| `kPa` \| `MPa` \| `GPa` \| `kgf/m^2` \| `kgf/cm^2` \| `kgf/mm^2` \| `mbar` \| `bar` \| `kbar` \| `atm` \| `ksi` \| `psi` \| `mmHg` \| `inHg`
Default value	`0.101325 MPa`
Program usage name	`p_start_b`
Evaluatable	Yes

Details

The initial temperature of the gas in the chamber is A.

Units	`K` \| `degC` \| `degF` \| `degR` \| `deltaK` \| `deltadegC` \| `deltadegF` \| `deltadegR`
Default value	`293.15 K`
Program usage name	`T_start_a`
Evaluatable	Yes

Details

The initial temperature of the gas in the chamber is B.

Units	`K` \| `degC` \| `degF` \| `degR` \| `deltaK` \| `deltadegC` \| `deltadegF` \| `deltadegR`
Default value	`293.15 K`
Program usage name	`T_start_b`
Evaluatable	Yes