MapleSim Hydraulics Library from Modelon - MapleSim Help

Online Help

All Products    Maple    MapleSim


Home : Support : Online Help : MapleSim Toolboxes : MapleSim Hydraulics Library from Modelon : Valves : ModelonHydraulics/Valves/ThreePortValve

MapleSim Hydraulics Library from Modelon

Three Port Valve  Three port valve with second-order spool dynamics and nonlinearities

The Three Port Valve component describes a three port valve with second-order spool dynamics. The laminar/turbulent flow through the valve is modeled as flow through an orifice without cavitation.

The commanded relative opening of the valve is input at command. The parameter qnom gives the nominal flow rate of the fully opened valve at the pressure drop dpnom. The parameter dleak gives the equivalent diameter of an orifice to describe the leakage flow if the valve is closed.

Amax=qnom12ρk2Δpnom

Aleak=14πdleak2

The position of the spool is modeled as a second-order system with natural frequency ω0, damping damp, limits for the velocity, and hysteresis for the position. The input variable is command and the output variable is position [-1 ... 1]. The flow area depends linearly on the spool position. For overlap = 0 the flows are given by:

position1 from command1

Flow from A  T. Flow area from A  T: Amax+Aleak. Flow area from P  A: Aleak.

1<position < 0 from 1<command < 0

Flow from A  T. Leakage from P  A. Flow area from A  T: Amax&plus;Aleakposition. Flow area from P  A: Aleak.

position&equals;0 from command&equals;0

Leakage from P  A and from  A  T.

0<position < 1 from 0<command < 1

Flow from P  A. Leakage from A  T.

1position from 1command

Flow from P  A. Leakage from A  T.

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

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

and/or

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

and/or

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

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

Related Components

Name

Description

Servo Valve

Valve with second-order spool dynamics and nonlinearities. Flow area depends linearly on spool position.

Prop Valve

Valve with second-order spool dynamics and nonlinearities. Flow area depends not linearly on spool position, usually large overlap.

 

Variables

Connections

Parameters

Variables

Name

Value

Units

Description

Modelica ID

VA

 

 

 

VolumeA

VT

 

 

 

VolumeT

VP

 

 

 

VolumeP

spoolDynamics

 

 

 

spoolDynamics

valveNoStates

 

 

 

valveNoStates

pAsummary

valveNoStates.port_A.p

Pa

Pressure at port A

summary_pA

pPsummary

valveNoStates.p[P]

Pa

Pressure at port P

summary_pP

pTsummary

valveNoStates.port_T.p

Pa

Pressure at port T

summary_pT

&Delta;pPAsummary

[1]

Pa

Pressure drop

summary_dp_PA

&Delta;pATsummary

[2]

Pa

Pressure drop

summary_dp_AT

qPAsummary

valveNoStates.morpa.q

m3s

Flow rate flowing port_P to port_A

summary_qPA

qATsummary

valveNoStates.morat.q

m3s

Flow rate flowing port_P to port_A

summary_qAT

[1] valveNoStates.port_P.pvalveNoStates.port_A.p

[2] valveNoStates.port_A.pvalveNoStates.port_T.p

Connections

Name

Description

Modelica ID

portA

Port A, one of valve connections to actuator or motor

port_A

portP

Port P, where oil enters the component from the pump

port_P

portT

Port T, where oil flows to the tank

port_T

command

Command signal for valve position

command

oil

 

oil

Parameters

General Parameters

Name

Default

Units

Description

Modelica ID

use volume A

true

 

If true, a volume is present at port_A

useVolumeA

use volume P

true

 

If true, a volume is present at port_P

useVolumeP

use volume T

true

 

If true, a volume is present at port_T

useVolumeT

VA

10-6

m3

Geometric volume at port A

volumeA

VP

10-6

m3

Geometric volume at port P

volumeP

VT

10-6

m3

Geometric volume at port T

volumeT

&Delta;Tsystem

0

K

Temperature offset from system temperature

dT_system

Actuation Parameters

Name

Default

Units

Description

Modelica ID

ω0

500

rads

Natural frequency of spool

omega0

damp

710

 

Damping coefficient of spool

damp

overlap

0.02

 

Overlap relative to max. displacement = 1

overlap

hyst

0.005

 

Half of hysteresis width

hyst

vmax

100

 

Max. spool velocity [1/s]

vmax

Flow Parameters

Name

Default

Units

Description

Modelica ID

dleak

10-6

m

Diameter of equivalent orifice to model leakage of closed valve

dleak

qnomPA

8.33·10-4

m3s

Nominal flow rate

qnompa

&Delta;pnomPA

3.5·106

Pa

Pressure drop at qnom

dpnompa

k1PA

10

 

Laminar part of orifice model

k1pa

k2PA

2

 

Turbulent part of orifice model, k2&equals;1Cd2

k2pa

CdPA

1k2PA

 

Max discharge coefficient

C_dpa

λcPA

2k1PAk2PA

 

Critical flow number

lambdacpa

qnomAT

8.33·10-4

m3s

Nominal flow rate

qnomat

&Delta;pnomAT

3.5·106

Pa

Pressure drop at qnom

dpnomat

k1AT

10

 

Laminar part of orifice model

k1at

k2AT

2

 

Turbulent part of orifice model, k2&equals;1Cd2

k2at

CdAT

1k2AT

 

Max discharge coefficient

C_dat

λcAT

2k1ATk2AT

 

Critical flow number

lambdacat

Transition

1

 

Transition model

Transition

See Also

Prop Valve

Servo Valve

Valves

MapleSim Hydraulics Library from Modelon Overview

 


Download Help Document

Was this information helpful?



Please add your Comment (Optional)
E-mail Address (Optional)
What is ? This question helps us to combat spam