Modelica.Fluid.Valves.BaseClasses.ValveCharacteristics

Functions for valve characteristics

Information

Extends from Modelica.Icons.VariantsPackage (Icon for package containing variants).

Package Content

Name	Description
baseFun	Base class for valve characteristics
linear	Linear characteristic
one	Constant characteristic
quadratic	Quadratic characteristic
equalPercentage	Equal percentage characteristic

Modelica.Fluid.Valves.BaseClasses.ValveCharacteristics.baseFun

Base class for valve characteristics

Information

This is a partial function that defines the interface of valve characteristics. The function returns "rc = valveCharacteristic" as function of the opening "pos" (in the range 0..1):

    dp = (zeta_TOT/2) * rho * velocity^2
m_flow =    sqrt(2/zeta_TOT) * Av * sqrt(rho * dp)
m_flow = valveCharacteristic * Av * sqrt(rho * dp)
m_flow =                  rc * Av * sqrt(rho * dp)

Extends from Modelica.Icons.Function (Icon for functions).

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Outputs

Modelica.Fluid.Valves.BaseClasses.ValveCharacteristics.linear

Linear characteristic

Information

Extends from baseFun (Base class for valve characteristics).

Inputs

Outputs

Modelica.Fluid.Valves.BaseClasses.ValveCharacteristics.one

Constant characteristic

Information

Extends from baseFun (Base class for valve characteristics).

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Outputs

Modelica.Fluid.Valves.BaseClasses.ValveCharacteristics.quadratic

Quadratic characteristic

Information

Extends from baseFun (Base class for valve characteristics).

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Outputs

Modelica.Fluid.Valves.BaseClasses.ValveCharacteristics.equalPercentage

Equal percentage characteristic

Information

d(rc)/d(pos) = k d(pos).

The constant k is expressed in terms of the rangeability, i.e., the ratio between the maximum and the minimum useful flow coefficient:

rangeability = exp(k) = rc(1.0)/rc(0.0).

The theoretical characteristic has a non-zero opening when pos = 0; the implemented characteristic is modified so that the valve closes linearly when pos < delta.

Extends from baseFun (Base class for valve characteristics).

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Outputs