modelInversePowerLaws
Test model for power law flow function and its inverse
Extends from Modelica.Icons.Example (Icon for runnable examples).
Information
This model tests the inverse formulation of the power law flow functions for three values of the flow exponent: n=1 (laminar flow), n=1.25, and n=2 (turbulent flow).
The pressure difference dp and dpCalc need to
be equal up to the solver tolerance, except for a small neighborhood
around the origin. In this neighborhood around the origin, the functions
Buildings.Fluid.BaseClasses.FlowModels.powerLaw_dp
and
Buildings.Fluid.BaseClasses.FlowModels.powerLaw_m_flow
do not have an analytic expression for their inverse function and hence
the implementation of the inverse function slightly differs.
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Real | k | 0.5 | |
| Real[3] | n | {1, 1/0.8, 2} | Flow exponent, n=1 for laminar, n=2 for turbulent |
| Modelica.Units.SI.MassFlowRate | m_flow_nominal | 1 | Nominal flow rate |
| Modelica.Units.SI.MassFlowRate | m_flow_turbulent | m_flow_nominal*0.3 | Mass flow rate where transition to turbulent flow occurs |
Components
| Type | Name | Default | Description |
|---|---|---|---|
| Modelica.Units.SI.MassFlowRate[3] | m_flow | ||
| Modelica.Units.SI.PressureDifference | dp | Pressure difference | |
| Modelica.Units.SI.PressureDifference[3] | dpCalc | Pressure difference computed by the flow functions | |
| Modelica.Units.SI.Pressure[3] | deltaDp | Pressure difference between input and output to the functions | |
| Modelica.Units.SI.Time | dTime | 2 |
Revisions
-
May 30, 2026, by Michael Wetter:
First implementation.
This is for Buildings, #4620.