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MapleSim Hydraulics Library from Modelon

Relief Valve  Static model of a relief valve

The Relief Valve component describes a relief valve. The resistance depends on the pressure differential, Δp=pApB:

&Delta;p<pclosed

Leakage from high pressure port to low pressure port only. q&equals;&Delta;pGleak

pclosed<&Delta;p < popen

Working range. Valve is partially open.

popen<&Delta;p

Valve is wide open. q&equals;&Delta;pGopen

 

The mass and flow forces are not included. Use the modifier(s)

VolumeA(port_A(p(start=1e5,fixed=true)))

and/or

VolumeB(port_A(p(start=1e5,fixed=true)))

to set the initial condition(s) for the pressure of the lumped volume(s) Pa.

Events

There is a new boolean reduceEvents (selected by default) in the Advanced section under the Inspector tab. Selecting reduceEvents lets the model use noEvents(expr) to generate fewer events for boolean expressions that should not generate events. In some cases the solver might reduce the stepsize too much and generate a lot of steps. If this happens, try clearing reduceEvents.

Related Components

Name

Description

Relief Valve No States

Ideal model of a relief valve, additional information.

Connections

Name

Description

Modelica ID

portA

Layout of port where oil flows into an element (0<mflow, pB<pA means 0<&Delta;p)

port_A

portB

Hydraulic port where oil leaves the component (mflow<0, pB<pA means 0<&Delta;p)

port_B

oil

 

oil

Parameters

General Parameters

Name

Default

Units

Description

Modelica ID

&Delta;Tsystem

0

K

Temperature offset from system temperature

dT_system

use volume A

true

 

If true, a volume is present at port_A

useVolumeA

use volume B

true

 

If true, a volume is present at port_B

useVolumeB

VA

10-6

m3

Geometric volume at port A

volumeA

VB

10-6

m3

Geometric volume at port B

volumeB

pclosed

1.9·107

Pa

Valve closed if &Delta;p smaller

pclosed

popen

2.05·107

Pa

Valve wide open if &Delta;p higher

popen

Gleak

1.11·10-12

m3sPa

Conductance of leakage of closed valve

GLeak

Gopen

1.67·10-9

m3sPa

Conductance of wide open valve

GOpen

Advanced Parameters

Name

Default

Units

Description

Modelica ID

reduce events

true

 

 

reduceEvents

See Also

Relief Valve No States, Valves, MapleSim Hydraulics Library from Modelon Overview


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