Relief Valve - MapleSim Help

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Relief Valve

Relief valve with opening area linearly dependent on pressure difference

 

Description

Optional Volumes

Connections

Parameters

Description

The Relief Valve component models a hydraulic relief valve as a sharp-edge orifice with the orifice area dependent on the pressure across the valve.

The area varies linearly from Aclosed to Aopen as the pressure varies from pclosed to popen, and remains at the endpoints for pressures outside this range.

Based on the orifice area, the pressure vs flow rate relationships are derived by the formulation used in the Orifice component.

Optional Volumes

The boolean parameters Use volume A and Use volume B, when true, add optional volumes VA  and VB to ports A and B, respectively. See Port Volumes for details.

If two orfices or valves are connected, enabling a volume at the common port reduces the the stiffness of the system and improves the solvability.

Connections

Name

Description

Modelica ID

portA

Upstream hydraulic port

portA

portB

Downstream hydraulic port

portB

Parameters

General Parameters

Name

Default

Units

Description

Modelica ID

Cd

710

 

Flow-discharge coefficient

Cd

Cr

12

 

Reynolds number at critical flow

ReCr

pclosed

1.9·107

Pa

Pressure at which valve is fully closed (A=Aclosed)

pclosed

popen

2.05·107

Pa

Pressure at which valve is fully open (A = A_open)

popen

Aopen

1·10−5

m2

Valve area when fully open

Aopen

Aclosed

1·10−12

m2

Valve area when closed (leakage)

Aclosed

Volume Parameters

Name

Default

Units

Description

Modelica ID

Use volume A

false

 

When true a hydraulic volume chamber is added to portA

useVolumeA

VA

1·10−6

m3

Volume of chamber A

Va

Use volume B

false

 

When true a hydraulic volume chamber is added to portB

useVolumeB

VB

1·10−6

m3

Volume of chamber B

Vb

For more information see Port Volumes.

See Also

Hydraulics Library

Valves