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/CheckValve

MapleSim Hydraulics Library from Modelon

Check Valve  Spring-loaded check valve with laminar/turbulent flow

The Check Valve component describes a spring-loaded check valve with laminar/turbulent flow. 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

Valve is partially open.

popen<&Delta;p

Valve is wide open. Flow mode depends on Reynolds number. Resistance modeled as an orifice in parallel with laminar resistance.

 

In some cases it is either necessary or helpful to include the dynamics of a check valve: the poppet needs some time to close or open the flow path. This effect is modeled by a first order system. The parameter tau_ball (found in the General section under the Properties tab ( )) gives the time to open or close the valve 95%.

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.

Related Components

Name

Description

Check Valve Two

Spring-loaded check valve with laminar/turbulent flow (different characteristic)

Check Valve No States

Ideal spring-loaded check valve with laminar/turbulent flow, additional information

 

Equations

Variables

Connections

Parameters

Equations

ν&equals;Modelica.Media.Air.MoistAir.Utilities.spliceFunctionx&equals;&Delta;p&comma;pos&equals;νoilp&equals;pAabs&comma;T&equals;T&comma;vair&equals;vgasoil&comma;psat&equals;psat&comma;neg&equals;νoilp&equals;pBabs&comma;T&equals;T&comma;vair&equals;vgasoil&comma;psat&equals;psat&comma;&Delta;x&equals;100

ρ&equals;Modelica.Media.Air.MoistAir.Utilities.spliceFunctionx&equals;&Delta;p&comma;pos&equals;ρoilp&equals;pAabs&comma;T&equals;T&comma;vair&equals;vgasoil&comma;psat&equals;psat&comma;neg&equals;ρoilp&equals;pBabs&comma;T&equals;T&comma;vair&equals;vgasoil&comma;psat&equals;psat&comma;&Delta;x&equals;100

T&equals;T0oil&plus;&Delta;Tsystem

q&equals;mflowAρ

&Delta;p&equals;pAlimitedpBlimited

pAabs&equals;pA&plus;patmoil

pAlimited&equals;maxpA&comma;pvapouroilpatmoil

pBabs&equals;pB&plus;patmoil

pBlimited&equals;maxpB&comma;pvapouroilpatmoil

Variables

Name

Value

Units

Description

Modelica ID

&Delta;p

 

Pa

Pressure drop

dp

q

 

m3s

Flow rate flowing into port_A

q

pAlimited

 

Pa

Limited gauge pressure

pA_limited

pBlimited

 

Pa

Limited gauge pressure

pB_limited

ρ

 

kgm3

Upstream density

rho

ν

 

m2s

Upstream kinematic viscosity

nu

pAabs

 

Pa

Absolute pressure pA

pA_abs

pBabs

 

Pa

Absolute pressure pB

pB_abs

T

 

K

Local temperature

T

pAsummary

pA

Pa

Pressure at port A

summary_pA

pBsummary

pB

Pa

Pressure at port B

summary_pB

&Delta;psummary

&Delta;p

Pa

Pressure drop

summary_dp

qsummary

q

m3s

Flow rate flowing into port_A

summary_q

Phydsummary

&Delta;pq

W

Hydraulic Power

summary_HP

psat

[1]

Pa

Gas saturation pressure

p_sat

VA

 

 

 

VolumeA

VB

 

 

 

VolumeB

ChVnSDyn

 

 

 

ChVnSDyn

ChVnS

 

 

 

ChVnS

[1] oil.gasSaturationPressureT&equals;T&comma;vgas&equals;oil.vgas

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

105

Pa

Pressure to start opening the valve

pclosed

Gleak

10-12

m3sPa

Conductance of leakage

GLeak

orif

1

 

Orifice dimension

orif

d

0.001

m

Diameter of equivalent orifice

diameter

area

0.001

m2

Area of the equivalent orifice

area

pnom

106

Pa

Nominal pressure drop

pnom

qnom

1.89·10-5

m3s

Nominal volume flow rate

qnom

ρnom

865

kgm3

Nominal density

rhonom

τball

0

s

Time to open or close check valve 95%

tau_ball

Fully Open Parameters

Name

Default

Units

Description

Modelica ID

Transition

1

 

Transition model

Transition

k1

10

 

Laminar part of orifice model

k1

k2

2

 

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

k2

Cd

0.707

 

Max discharge coefficient

C_d

Partially Open Parameters

Name

Default

Units

Description

Modelica ID

reg type

2

 

Regularization type

regtype

G

1.53·10-11

m3sPa

Hydraulic conductance G&equals;&PartialD;q&PartialD;p

G

trans

100

 

Transition Reynolds number

Re_trans

popen

1.25·105

Pa

Pressure to open valve completely

popen

reg param

3

 

Regularization parameter

regparam

See Also

Check Valve No States

Check Valve Two

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