WOLFRAM SYSTEM MODELER

PumpVariable

Model of a pump with variable displacement and volumes

Diagram

Wolfram Language

In[1]:=
SystemModel["Hydraulic.PumpsAndMotors.PumpVariable"]
Out[1]:=

Information

This is a model of a pump with volumes, variable displacement setting, friction, and internal and external leakage. The axial speed is proportional to the flow rate:



The torque is proportional to the pressure difference:



where
:Mass flow rate
:Fluid density
D:Maximum displacement
u:Displacement setting
:Pressure difference between the ports
:Torque
:Angular velocity

The signal is limited to +/-1 and controls the flow according to the table below:

u>=1:Maximum flow from port a to port b
u=0:Only leakage flow from port a to port b
u<=-1:Maximum flow from port b to port a

Limitations

Volumetric efficiency is not included in the model.

Reference

Industrial Hydraulics Manual, 5th ed., Maumee, OH: Eaton Hydraulics Training Services, 2008 p. 164.

Parameters (8)

medium

Value: Oil()

Type: Medium

Description: Medium in the component

D

Value:

Type: Volume (m³)

Description: Displacement per revolution

externalLeakage

Value: 1e-12

Type: PressureDependentLeakage (m³/(s·Pa))

Description: Leakage between cylinders

internalLeakage

Value: 1e-12

Type: PressureDependentLeakage (m³/(s·Pa))

Description: Leakage between cylinders

frictionD

Value: 1

Type: RotationalDampingConstant (N·m·s/rad)

Description: Viscous friction

J

Value: 1

Type: MomentOfInertia (kg·m²)

Description: Moments of inertia

tankPressure

Value: 100000.0

Type: Pressure (Pa)

Description: Tank pressure

V

Value: 0.0001

Type: Volume (m³)

Description: Volume

Connectors (4)

port_b

Type: Port_b

port_a

Type: Port_a

flange

Type: Flange_a

e

Type: RealInput

Description: Displacement setting between -1 and 1

Components (13)

medium

Type: Medium

Description: Medium in the component

volume_b

Type: Volume

volume_a

Type: Volume

inertia

Type: Inertia

friction

Type: Damper

pumpMotorVariable

Type: BasicDisplacementMachine

externalLeakage_b

Type: RestrictionLaminar

tank_b

Type: Tank

tank_a

Type: Tank

externalLeakage_a

Type: RestrictionLaminar

internalLeakage_ab

Type: RestrictionLaminar

fixed1

Type: Fixed

limiter1

Type: Limiter

Used in Examples (1)

HydrostaticTransmission

Hydraulic.Examples.Rotation

Example circuit of a pump driving a motor