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MapleSim Hydraulics Library from Modelon

Sim Ori  Simple orifice model for turbulent flow with volumes at the ports

The Sim Ori component describes the turbulent flow through an orifice if no cavitation occurs using a simple textbook model. The pressure drop is modeled as in Sim Ori No States. Volumes may be added at the ports. 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].

Note: This model can cause severe numerical problems for the integration routine if the pressure drop dp becomes very small.

Related Components

Name

Description

Lam Res

Resistance with laminar flow and volumes at the ports.

Orifice

Recommended component. The component, based on the loss coefficient K, describes both flow regimes: laminar for very small Reynolds numbers and turbulent for higher Reynolds numbers (default model).

Ori Poly

The component describes both flow regimes, using an interpolation polynomial.

Ori Cav

Orifice component checking for cavitation.

Metering Ori

Metering Orifice (that is, component Orifice No States with variable diameter).

Two Orifices

Two orifices in series, one with variable the other with fixed flow area.

Restrictions[Basic]

Differences between basic models are shown by a figure.

 

Equations

Variables

Connections

Parameters

Equations

ν=Modelica.Media.Air.MoistAir.Utilities.spliceFunctionx=Δp,pos=νoilp=pAabs,T=T,vair=vgasoil,psat=psat,neg=νoilp=pBabs,T=T,vair=vgasoil,psat=psat,Δx=100

ρ=Modelica.Media.Air.MoistAir.Utilities.spliceFunctionx=Δp,pos=ρoilp=pAabs,T=T,vair=vgasoil,psat=psat,neg=ρoilp=pBabs,T=T,vair=vgasoil,psat=psat,Δx=100

T=T0oil+ΔTsystem

q=mflowAρ

Δp=pAlimitedpBlimited

pAabs=pA+patmoil

pAlimited=maxpA,pvapouroilpatmoil

pBabs=pB+patmoil

pBlimited=maxpB,pvapouroilpatmoil

Variables

Name

Value

Units

Description

Modelica ID

Δp

 

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

Δpsummary

Δp

Pa

Pressure drop

summary_dp

qsummary

q

m3s

Flow rate flowing into port_A

summary_q

Phydsummary

Δpq

W

Hydraulic Power

summary_HP

psat

[1]

Pa

Gas saturation pressure

p_sat

VA

 

 

 

VolumeA

VB

 

 

 

VolumeB

SOr

 

 

 

SOr

[1] oil.gasSaturationPressureT=T,vgas=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

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

d

0.001

m

Orifice diameter

diameter

Cd

0.707

 

Discharge coefficient

C_d

See Also

Metering Ori

Ori Cav

Ori Poly

Orifice

Orifice No States

Restrictions

Restrictions[Basic]

Sim Ori No States

Two Orifices

MapleSim Hydraulics Library from Modelon Overview

 


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