Package 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 Contents

NameDescription
VolumeFlowRateFlow model for generic resistance parameterized with the volume flow rate

Model 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) and Modelica.​Fluid.​Interfaces.​PartialTwoPortTransport (Partial element transporting fluid between two ports without storage of mass or energy).

Parameters

TypeNameDefaultDescription
BooleanallowFlowReversalsystem.​allowFlowReversal= true to allow flow reversal, false restricts to design direction (port_a -> port_b)
AbsolutePressuredp_start0.01 * system.p_startGuess value of dp = port_a.p - port_b.p
MassFlowRatem_flow_startsystem.​m_flow_startGuess value of m_flow = port_a.m_flow
MassFlowRatem_flow_smallif system.use_eps_Re then system.eps_m_flow * system.m_flow_nominal else system.m_flow_smallSmall mass flow rate for regularization of zero flow
Booleanshow_Ttrue= true, if temperatures at port_a and port_b are computed
Booleanshow_V_flowtrue= true, if volume flow rate at inflowing port is computed
Reala Coefficient for quadratic term
Realb Coefficient for linear term

Connectors

TypeNameDescription
FluidPort_aport_aFluid connector a (positive design flow direction is from port_a to port_b)
FluidPort_bport_bFluid connector b (positive design flow direction is from port_a to port_b)

Generated 2018-12-12 12:13:27 EST by MapleSim.