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MapleSim Hydraulics Library from Modelon

Sim Ori No States  Simple orifice model for turbulent flow

The Sim Ori No States component describes the turbulent flow through an orifice if no cavitation occurs using a simple textbook model:

q=ACd2Δpρ

Variables used in the above equations

q

Flow rate m3s

A

Area of the orifice m2

Cd

Discharge coefficient

ρ

Mass density, from FluidProp kgm3

Δp

Pressure drop across orifice Pa

The mass and flow forces are not included.

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

Related Components

Name

Description

Lam Res No States

Resistance with laminar flow.

Var Lam Res No States

Resistance with laminar flow and externally commanded conductance.

Orifice No States

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 No States

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

Ori Cav No States

Orifice component checking for cavitation.

Metering Ori No States

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

Two Orifices

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

Orifice N

Same as Orifice No States, but with the equations rearranged to compute Δp for given q.

Restrictions[Basic]

Differences between basic models are shown by a figure.

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

d

0.001

m

Orifice diameter

diameter

Cd

0.707

 

Max discharge coefficient

C_d

Constant Parameters

Name

Default

Units

Description

Modelica ID

orif

1

 

Orifice dimension

orif

flowcond

3

 

Flow condition

flowcond

Transition

1

 

Transition model

Transition

reg type

0

 

Regularization type

regtype

reg param

0

 

Regularization parameter

regparam

cavitation

false

 

Cavitation

cavitation

checkvalve

false

 

 

checkvalve

k1

0

 

Laminar part

k1

k2

0

 

k2&equals;1Cd2

k2

λc

0

 

Critical flow number

lambdac

0

m

Orifice length; 1<d

length

trans

0

 

Transition Reynolds number

Re_trans

ptrans

0

Pa

Transition pressure

p_trans

pclosed

0

Pa

Cracking pressure

p_closed

Gleak

0

m3sPa

Leakage conductance

G_Leak

Constants

Name

Value

Units

Description

Modelica ID

&alpha;[k]

0.649

 

 

alpha_k

See Also

Lam Res No States, Metering Ori No States, Ori Cav No States, Ori Poly No States, Orifice N, Orifice No States, Restrictions, Restrictions[Basic], Two Orifices, Var Lam Res No States, MapleSim Hydraulics Library from Modelon Overview


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