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MapleSim Hydraulics Library from Modelon

Orifice  Recommended orifice model with volumes at the ports

The Orifice component describes the laminar/turbulent flow through an orifice if no cavitation occurs. This is the recommended orifice component in the library and the mathematical model is also used for the metering orifice. See Metering Ori No States for the pressure drop description. 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].

Related Components

Name

Description

Lam Res

Resistance with laminar flow and volumes at the ports.

Ori Poly

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

Ori Cav

Orifice component checking for cavitation.

Sim Ori

Simple textbook component, using a constant discharge coefficient. It is valid for turbulent flow only; severe numerical problems for laminar flow.

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

OrinS

 

 

 

OrinS

[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

k1

10

 

Laminar part

k1

k2

2

 

k2&equals;1Cd2

k2

Cd

1k2

 

Max discharge coefficient

C_d

λc

2k1k2

 

Critical flow number

lambdac

Transition

1

 

Transition model

Transition

orif

[1]

 

Orifice dimension

orif

pnom

106

Pa

Nominal pressure drop

pnom

qnom

1.89·10-5

m3s

Nominal volume flow rate

qnom

ρnom

865

kgm3

Nominal density

rhonom

d

0.001

m

Orifice diameter

diameter

area

0.001

m2

Orifice area

area

[1] Hydraulics.Restrictions.Basic.PressureDrop.orifinput.D

See Also

Lam Res

Metering Ori

Ori Cav

Ori Poly

Orifice No States

Restrictions

Restrictions[Basic]

Sim Ori

Two Orifices

MapleSim Hydraulics Library from Modelon Overview

 


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