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 in the turbulent region.
However, for small absolute pressure drops, the results differ slightly
because the functions
Buildings.Fluid.BaseClasses.FlowModels.powerLaw_dp
and
Buildings.Fluid.BaseClasses.FlowModels.powerLaw_m_flow
are not exact inverses.
The exact inverses are
Buildings.Fluid.BaseClasses.FlowModels.powerLaw_dp_inv
and
Buildings.Fluid.BaseClasses.FlowModels.powerLaw_m_flow_inv.
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
-
October 25, 2026, by Michael Wetter:
Updated documentation.
This is for Buildings, #4798. -
May 30, 2026, by Michael Wetter:
First implementation.
This is for Buildings, #4620.