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MapleSim Hydraulics Library from Modelon

Three Way Flow Control  Three way flow control valve

The Three Way Flow Control component describes a three way flow control valve (bypass type). The commanded flow rate is given by the input signal at qCommand [m3/s]. If the demanded flow rate is in the working range of the valve, the conductance of the valve is calculated such that the demanded flow rate is achieved with a minimum pressure at port A. The conductance of the flow control part of the valve is limited by GMax (that is, a wide open valve) and GMin (that is, a closed valve with leakage from A to B only). The conductance of the pressure control part of the valve is limited by GOpen (wide open valve) and GLeak (valve closed, leakage from A to T only). As no dynamic effects are modeled, the jump phenomenon does not occur.

Setting parameters

Δpnom

This parameter gives the nominal pressure differential from port_A to port_B if the valve is in the operating range. Typical values: 3-7e5 Pa.

GMax

The maximum flow rate from A to B for a given Δpnom is given by: qmax=dpnomGMax This gives the nominal working range of the valve.

GMin

Conductance of closed series flow control valve (that is, leakage from A to B if commanded flow rate = 0).

dpopen

The relief valve is wide open if the pressure differential across that valve is higher than dpopen.

GOpen

The maximum flow rate from A to T where the relief valve is in the operating range is given by: qmax_relief=dpopenGOpen If the pump flow rate at port_A is greater than qmax_relief while commanded flow rate = 0, the pressure at port_A will be greater than dpopen.

GLeak

Conductance of closed relief valve (that is, leakage from A to T regardless of the commanded flow rate): GLeakport_A.pport_B.p=q_leak_relief

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)))

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.

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

Ser Flow Cont

Serial flow control valve, restriction type

Connections

Name

Description

Modelica ID

portA

port_A: oil mostly enters the element

port_A

portB

Hydraulic port where oil enters or leaves the element

port_B

portT

Hydraulic port where oil mostly leaves the element

port_T

oil

 

oil

qCommand

Command signal for flow rate

qCommand

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 B

true

 

If true, a volume is present at port_B

useVolumeB

use volume T

true

 

If true, a volume is present at port_T

useVolumeT

VA

10-6

m3

Geometric volume at port A

volumeA

VB

10-6

m3

Geometric volume at port B

volumeB

VT

10-6

m3

Geometric volume at port T

volumeT

ΔTsystem

0

K

Temperature offset from system temperature

dT_system

Δpnom

5.·105

Pa

Nominal pressure differential from A to B

dpnom

Gmax

3.03·10-10

m3sPa

Conductance of wide open series flow control valve

GMax

Gmin

3.03·10-16

m3sPa

Conductance of closed series flow control valve, i. e. leakage

GMin

Δpopen

2.·105

Pa

Relief valve wide open if &Delta;popen<&Delta;p

dpopen

Gopen

1.67·10-9

m3sPa

Conductance of wide open relief valve

GOpen

Gleak

1.11·10-12

m3sPa

Conductance of closed relief valve, i. e. leakage

GLeak

Advanced Parameters

Name

Default

Units

Description

Modelica ID

reduce events

true

 

If true, generate less events

reduceEvents

See Also

Ser Flow Cont, Valves, MapleSim Hydraulics Library from Modelon Overview


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