Hot Oil Shuttle Valve - MapleSim Help
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Hot Oil Shuttle Valve

Shuttle valve which directs flow from lower pressure inlet

 

Description

Equations

Variables

Connections

Parameters

Description

The Hot Oil Shuttle Valve component allows flow out of port C from the either port A or port B, depending which has the lower pressure. Based on the orifice area, the pressure vs. flow rate relationship is calculated by the formulation used in the Orifice component.

Formulation Approximate

One of two approaches can be selected for modeling the flow in the device. When the boolean parameter Use constant Cd  is true, a constant coefficient of discharge (Cd) is used, otherwise a variable coefficient of discharge with maximum value (Cdmax) and a critical flow number (Critno) are used.

Optional Volumes

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

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

Equations

{pAC=π4ρνqAA16qAA4π2Acs12ν4+Cr414Cd2Acs1πAcs1\seConstantCdqAA=Cdmaxtanh42Acs1pACπρνCritnoAcs12pACρsignpACotherwise

{pBC=π4ρνqBB16qBB4π2Acs22ν4+Cr414Cd2Acs2πAcs2\seConstantCdqBB=Cdmaxtanh42Acs2pBCπρνCritnoAcs22pBCρsignpBCotherwise

{Acs1=AiAi=AtExactAcs1=minAopen,maxAclose,Ai,tcdAi1dt+Ai=Atotherwise

Acs2=Aopen+AcloseAcs1

At=AopenAclose1212tanhepspAB

VfA={Va1+pAElUse volume A0otherwise qVA={V.fAUse volume A0otherwise

VfB={Vb1+pBElUse volume B0otherwise qVB={V.fBUse volume B0otherwise

VfC={Vc1+pCElUse volume C0otherwise qVC={V.fCUse volume C0otherwise

pAB=pApBpAC=pApCpBC=pBpC

qAA=qAqVAqBB=qBqVBqCC=qCqVC

qA+qB+qCqVAqVBqVC=0

Variables

Name

Units

Description

Modelica ID

pX

Pa

Pressure at port X

pX

pXY

Pa

Pressure drop from port X  to port Y

pXY

qXX

m3s

Flow rate into port X

qXX

qVX

m3s

Flow rate into port X's optional volume

qVX

VfX

m3

Effective volume at port X

VfX

ACS1

m2

Cross-sectional area from A to B

Acs[1]

ACS2

m2

Cross-sectional area from B to C

Acs[2]

Ai

m2

Filtered interpolated area

Ai

At

m2

Interpolated area

At

u1

ms

Fluid velocity from A to B

u1

u2

ms

Fluid velocity from B to C

u2

X,YA,B,C

Connections

Name

Description

Modelica ID

portA

Hydraulic port of left inlet

portA

portB

Hydraulic port of right inlet

portB

portC

Hydraulic port of bottom outlet

portC

Parameters

General

Name

Default

Units

Description

Modelica ID

Aclose

1·10−12

m2

Orifice area when closed (leakage)

Aclose

Aopen

1·10−5

m2

Orifice area when fully open

Aopen

ε

0.2

1Pa

Positive factor that effects the transition between ports A and B

eps

Exact

false

 

When false (not checked) first-order dynamics are used for the valve area

Exact

tc

0.1

s

Time constant

tc

Orifice

Name

Default

Units

Description

Modelica ID

Use constant Cd

true

 

True (checked) means a constant coefficient of discharge is implemented, otherwise a variable Cd is used in flow calculations

UseConstantCd

Cd

0.7

 

Flow-discharge coefficient; used when Use constant Cd is true

Cd

ReCr

12

 

Reynolds number at critical flow; used when Use constant Cd is true

ReCr

Cdmax

0.7

 

Maximum flow-discharge coefficient; used when Use constant Cd is false

Cd_max

Critno

1000

 

Critical flow number; used when Use constant Cd is false

Crit_no

Optional Volumes

Name

Default

Units

Description

Modelica ID

Use volume A

false

 

True (checked) means a hydraulic volume chamber is added to portA

useVolumeA

VA

1·10−6

m3

Volume of chamber A

Va

Use volume B

false

 

True (checked) means a hydraulic volume chamber is added to portB

useVolumeB

VB

1·10−6

m3

Volume of chamber B

Vb

Use volume C

false

 

True (checked) means a hydraulic volume chamber is added to portC

useVolumeC

VC

1·10−6

m3

Volume of chamber C

Vc

For more information see Port Volumes.

See Also

Hydraulics Library

Valves