Modelica.Fluid.Fittings.GenericResistances

Flow models for generic resistances

Information

The geometry parameters of energy devices necessary for the pressure loss calculations are often not exactly known. Therefore the modelling of the detailed pressure loss calculation has to be simplified. In this package components are present that provide different forms of such approximations.

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

Package Content

Name Description
Modelica.Fluid.Fittings.GenericResistances.VolumeFlowRate VolumeFlowRate Flow model for generic resistance parameterized with the volume flow rate

Modelica.Fluid.Fittings.GenericResistances.VolumeFlowRate Modelica.Fluid.Fittings.GenericResistances.VolumeFlowRate

Flow model for generic resistance parameterized with the volume flow rate

Information

This component models a generic resistance parameterized with the volume flow rate:

    dp     = a*V_flow^2 + b*V_flow
    m_flow = rho*V_flow

with

a as quadratic coefficient [Pa*s^2/m^6],
b as linear coefficient [Pa*s/m3],
dp as pressure loss [Pa],
m_flow as mass flow rate [kg/s],
rho as density of fluid [kg/m3],
V_flow as volume flow rate [m3/s].

The geometry parameters of energy devices necessary for the pressure loss calculations are often not exactly known. Therefore the modelling of the detailed pressure loss calculation has to be simplified. This components use a linear and a quadratic dependence of the pressure loss on the volume flow rate. It is assumed that neither mass nor energy is stored in this component. In the model basically a function is called to compute the mass flow rate as a function of pressure loss. Also the inverse of this function is defined, and a tool might use this inverse function instead, in order to avoid the solution of a nonlinear equation.

The details of the model are described in the documentation of the underlying function.

Extends from Modelica.Fluid.Dissipation.Utilities.Icons.PressureLoss.General_i (Icon for general pressure drop), Modelica.Fluid.Interfaces.PartialTwoPortTransport (Partial element transporting fluid between two ports without storage of mass or energy).

Parameters

NameDescription
replaceable package MediumMedium in the component
dp = a*V_flow^2 + b*V_flow
aCoefficient for quadratic term [(Pa.s2)/m6]
bCoefficient for linear term [(Pa.s)/m3]
Assumptions
allowFlowReversal= true to allow flow reversal, false restricts to design direction (port_a -> port_b)
Advanced
dp_startGuess value of dp = port_a.p - port_b.p [Pa]
m_flow_startGuess value of m_flow = port_a.m_flow [kg/s]
m_flow_smallSmall mass flow rate for regularization of zero flow [kg/s]
Diagnostics
show_T= true, if temperatures at port_a and port_b are computed
show_V_flow= true, if volume flow rate at inflowing port is computed

Connectors

NameDescription
port_aFluid connector a (positive design flow direction is from port_a to port_b)
port_bFluid connector b (positive design flow direction is from port_a to port_b)
Automatically generated Thu Dec 19 17:20:11 2019.