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MapleSim Hydraulics Library from Modelon

Poppet Lift  Ball poppet lift with sharp edge seat

This is a model of a poppet lift.

 

Equations

Variables

Connections

Parameters

Equations

X=preXmaxpreXmax<s_rel_aswitch+X_0andpremaX=trueX=maxXmin&comma;s_rel_aswitch+X_0otherwise

fflow=2noEvent&Delta;pflowareacosalphak2TransitionType=1fflow=2noEvent&Delta;pCdmaxflowareacosalphaotherwise

qunsigned=`Modelica.Fluid.Utilities.regRoot`max0&comma;k12ν2ρ2+32flowareak2`Modelica.Fluid.Utilities.regRoot`&Delta;p2ρπk1νρ`Modelica.Fluid.Utilities.regRoot`max0&comma;flowareaπ4k2ρTransitionType=1qunsigned=Cdmax`Modelica.Math.tanh`2λλcflowarea`Modelica.Fluid.Utilities.regRoot`2`Modelica.Fluid.Utilities.regRoot`&Delta;p2ρotherwise

msim/ALGORITHMmsim/WHENflowareamax<flowarea&comma;msim/ASSIGNXmax&comma;preX&comma;msim/ASSIGNmaX&comma;true&comma;flowarea<flowareamax&comma;msim/ASSIGNmaX&comma;false

0&equals;fswitch&plus;fA&plus;fB

0&equals;fswitch&plus;fAsupport&plus;fBsupport

ν&equals;νoilpabs&equals;pxabs&comma;T&equals;T&comma;vair&equals;vgasoil&comma;psat&equals;psat

ρ&equals;ρoilpabs&equals;pxabs&comma;T&equals;T&comma;vair&equals;vgasoil&comma;psat&equals;psat

D&equals;4flowareaπ2a&plus;2R

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

V2&equals;V02XXminV02XXminArod_2+`Hydraulics.Elements.Templates.sphericalCapVolume`_msim_R=R&comma;_msim_a=r+VconeVsliceotherwise

Vcone&equals;13πr2X

Vslice&equals;Hydraulics.Elements.Templates.sphericalCapVolume_msim_R&equals;R&comma;_msim_a&equals;a&plus;13πa2R2a2

a&equals;R1&plus;X2r2

f&equals;πa2&plus;Arod_1p1&plus;πa2&plus;Arod_2p2fflow

λ=D`Modelica.Fluid.Utilities.regRoot`2`&Delta;p``&rho;``&nu;`

lift&equals;XXmin

p1abs&equals;p1&plus;patmoil

p2abs&equals;p2&plus;patmoil

VA&equals;V1

pxabs&equals;p1absxp&plus;p2abs1xp

qLmin&equals;60000qunsigned

sarel&equals;sAsAsupport

xp&equals;Modelon.Math.Smoothing.cubicStep&Delta;p&plus;12

&Delta;p&equals;p1p2

cosalpha&equals;aR

flowarea&equals;flowarea_nom

flowarea_nom&equals;Hydraulics.Elements.Templates.truncConeArea_msim_R&equals;r&comma;_msim_X&equals;XR2a2&comma;_msim_h&equals;X

portA.m_flow&equals;noEventρqunsigned0&Delta;pρqunsignedotherwise

portA1.V&equals;V2

sabrel&equals;L

sabrel&equals;switchsBsA

sBsupport&equals;Lswitch&plus;sAsupport

p1&equals;pA

p2&equals;portA1.p

V1&plus;V2&equals;V01&plus;V02XXminArod_2Arod_1

mflowA1&plus;mflowA&equals;0

Variables

Name

Value

Units

Description

Modelica ID

srela

 

m

Relative position of flangeA wrt supportA

s_rel_a

srelab

 

m

Relative position of flangeB wrt flangeA

s_rel_ab

f

 

N

Force acting in positive direction of flangeA

f

λ

 

 

Flow coefficient

lambda

qunsigned

 

 

Absolute value of volume flowrate

qunsigned

qLmin

 

 

Volume flowrate in l/min

qLmin

X

 

 

Distance from poppet center to seat

X

lift

 

 

Poppet lift

lift

fflow

 

N

Static flow forces

fflow

cosalpha

 

 

Defines direction of flow forces

cosalpha

flowarea

 

m2

Effective orifice area

flowarea

flowareanom

 

m2

Orifice area (no saturation)

flowarea_nom

D

 

m

Hydraulic diameter

D

V1

 

m3

Volume, poppet side

V1

V2

 

m3

Volume, seat side

V2

T

 

K

Temperature

T

&Delta;p

 

Pa

Pressure difference over the valve

dp

p1

 

Pa

Pressure, poppet side

p1

p2

 

Pa

Pressure, seat side

p2

ρ

 

kgm3

Fluid density in the chamber

rho

ν

 

m2s

Fluid viscosity in the chamber

nu

psat

[1]

Pa

Gas saturation pressure

p_sat

p1abs

 

Pa

Absolute pressure, used for all property calls

p1_abs

p2abs

 

Pa

Absolute pressure, used for all property calls

p2_abs

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

Connections

Name

Description

Modelica ID

supportA

 

supportA

supportB

 

supportB

flangeA

 

flangeA

flangeB

 

flangeB

oil

Fluid property model

oil

portA

 

portA

portA1

 

portA1

Parameters

General Parameters

Name

Default

Units

Description

Modelica ID

L

 

m

Element length

L

reverse

false

 

Reverse the sign convention, see documentation for details

reverse

switch

-1reverse&equals;true1otherwise

 

-1 if reverse, else 1

switch

R

0.1

m

Poppet radius

R

r

0.05

m

Throat radius

r

Rrod1

 

m

Rod radius, poppet side

Rrod_1

Rrod2

 

m

Rod radius, seat side

Rrod_2

lift0

0

m

Poppet lift in neutral position

lift_0

V01

[1]

m3

Volume, poppet side, when closed valve

V01

V02

[1]

m3

Volume, seat side, when closed valve

V02

TransitionType

1

 

Type of transition

TransitionType

k1

10

 

Laminar part of flow model

k1

k2

2.04

 

Turbulent part of flow model

k2

Cdmax

0.7

 

Discharge coefficient

Cdmax

λc

14

 

Critical flow number

lambdac

&Delta;Tsystem

0

K

Temperature offset from system temperature

dT_system

[1] 2.0πLR2

Constant Parameters

Name

Default

Units

Description

Modelica ID

Xmin

R2r2

 

minimum distance between ball center and seat

Xmin

flowareamax

[1]

m2

Maximum flow area

flowareamax

Arod1

[2]

m2

Rod area, poppet side

Arod_1

Arod2

[3]

m2

Rod area, seat side

Arod_2

X0

lift0+Xmin_

m

distance from seat to poppet center

X_0

[1] πr2Arod_2

[2] πRrod_12

[3] πRrod_22

See Also

Elements

MapleSim Hydraulics Library from Modelon Overview

 


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