VariableDisplacementPump

Partial Pump

    VariableDisplacementPump

Library

Components/Pumps

Description

Model of a pump with variable displacement volume and losses.

The main parameters of the pump are its maximum Displacement volume and the Rotational moment of inertia. The displacement volume can be adjusted by using the setpoint signal:

setpoint = 0displacement volume = 0
setpoint > 1displacement volume = dispVolume
sign(w) = sign(fluidPortA.mFlow)
setpoint < -1displacement volume = dispVolume
sign(w) = -sign(fluidPortA.mFlow)
1 > setpoint > 0displacement volume = dispVolume * setpoint
sign(w) = sign(fluidPortA.mFlow)
-1 < setpoint < 0displacement volume = dispVolume * setpoint
sign(w) = -sign(fluidPortA.mFlow)

The losses are parameterised by providing volumetric and mechanical efficiencies Volumetric efficiency and Mechanical efficiency for a given operating point. The operating point is characterised by a reference pressure difference Reference pressure difference and a corresponding shaft speed Reference speed. Based on the entered values, the parameters of a laminar throttle (volumetric losses) and a linear damper (representing the mechanical losses) are determined automatically. Unlike the efficiencies, the parameters of these two elements typically do not vary significantly with the operating conditions.

The parameter Ration external Leakage / total Leakage allows to split the leakage between internal and external leakage. A gear pump e. g. typically has no external leakage, Ration external Leakage / total Leakage has to be set to 0. In contrast, a piston pump has a significant external leakage (0.5 < Ration external Leakage / total Leakage <= 1).

Parameters

VariableDisplacementPump_0

NameLabelDescriptionData TypeValid Values

mo_dispVolume

dispVolume

Displacement volume

Scalar

mo_Jrot

Jrot

Rotational moment of inertia

Scalar

mo_deadVolume

deadVolume

Dead volume at ports

Scalar

mo_etaVol

etaVol

Volumetric efficiency @ nRef, dpRef

Scalar

mo_leakageReferenceDensity

leakageReferenceDensity

Reference density for volumetric efficiency

Scalar

mo_ratioLeakageExtern

ratioLeakageExtern

Ratio external Leakage / total Leakage

Scalar

mo_useLeakagePort

useLeakagePort

Enable leakage port, otherwise implicitly connected with tank

Number

0
1

mo_etaHm

etaHm

Mechanical efficiency @ nRef, dpRef

Scalar

mo_nRef

nRef

Reference speed (1/min)

Scalar

mo_dpRef

dpRef

Reference pressure difference

Scalar

mo_nominalVolumeFlow

nominalVolumeFlow

Scalar

mo_volumeFlowLoss

volumeFlowLoss

Scalar

mo_dvisc

dvisc

Scalar

VariableDisplacementPump_1

NameLabelDescriptionData TypeValid Values

mo_stateSelect

stateSelect

Priority to use phi and w as states

Structure

mo_stateSelect/choice1

StateSelect.never

Number

0
1

mo_stateSelect/choice2

StateSelect.avoid

Number

0
1

mo_stateSelect/choice3

StateSelect.default

Number

0
1

mo_stateSelect/choice4

StateSelect.prefer

Number

0
1

mo_stateSelect/choice5

StateSelect.always

Number

0
1

VariableDisplacementPump_2

NameLabelDescriptionData TypeValid Values

mo_forwardFluidProperties

forwardFluidProperties

Forward fluid properties between ports

Scalar

true
false

VariableDisplacementPump_3

NameLabelDescriptionData TypeValid Values

mo_volumeFlowA

volumeFlowA

volumeFlowA

Structure

mo_volumeFlowA/fixed

fixed

Cell of scalars

true
false

mo_volumeFlowA/start

start

Cell of scalars

mo_volumeFlowB

volumeFlowB

volumeFlowB

Structure

mo_volumeFlowB/fixed

fixed

Cell of scalars

true
false

mo_volumeFlowB/start

start

Cell of scalars

mo_pA

pA

pA

Structure

mo_pA/fixed

fixed

Cell of scalars

true
false

mo_pA/start

start

Cell of scalars

mo_pB

pB

pB

Structure

mo_pB/fixed

fixed

Cell of scalars

true
false

mo_pB/start

start

Cell of scalars

mo_phi

phi

phi

Structure

mo_phi/fixed

fixed

Cell of scalars

true
false

mo_phi/start

start

Cell of scalars

mo_w

w

w

Structure

mo_w/fixed

fixed

Cell of scalars

true
false

mo_w/start

start

Cell of scalars

mo_setpoint

setpoint

setpoint

Structure

mo_setpoint/fixed

fixed

Cell of scalars

true
false

mo_setpoint/start

start

Cell of scalars

Ports

NameTypeDescriptionIO TypeNumber

fluidPortA

implicit

Hydraulic port A

input

1

fluidPortB

implicit

Hydraulic port B

input

2

flange_a

implicit

input

3

flange_b

implicit

output

1

setpoint

implicit

input

4

Port 6

implicit

Hydraulic port Leakage

input

mo_useLeakagePort