modelPowerLaw_m_flow_inv_DerivativeCheck2
Model that checks the correct implementation of the 1st and 2nd order derivative of the inverse of the power law function
Extends from Modelica.Icons.Example (Icon for runnable examples).
Information
This model validates the implementation of Buildings.Fluid.BaseClasses.FlowModels.powerLaw_m_flow_inv and its first and second order derivatives Buildings.Fluid.BaseClasses.FlowModels.powerLaw_m_flow_inv_der and Buildings.Fluid.BaseClasses.FlowModels.powerLaw_m_flow_inv_der2. If the derivative implementation is wrong, the simulation will stop with an error.
Implementation
The pressure difference dp is increased non-linearly in order
for the first and second derivatives in
Buildings.Fluid.BaseClasses.FlowModels.powerLaw_m_flow_inv_der2
to be non-zero during part of the simulation.
The input sweeps through the laminar and the turbulent region.
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Real | k | 0.5 | Flow coefficient, k = m_flow/ dp^(1/n) |
| Real | n | 1.5 | Flow exponent, n=1 for laminar, n=2 for turbulent |
| Modelica.Units.SI.MassFlowRate | m_flow_turbulent | 0.1 | Mass flow rate where transition to turbulent flow occurs |
Components
| Type | Name | Default | Description |
|---|---|---|---|
| Modelica.Units.SI.MassFlowRate | m_flow | Mass flow rate | |
| Modelica.Units.SI.MassFlowRate | m_flow_comp | Comparison value for m_flow | |
| Real | der_m_flow | 1st order derivative of mass flow rate | |
| Real | der_m_flow_comp | 1st order derivative of comparison value for m_flow | |
| Modelica.Units.SI.PressureDifference | dp | Pressure difference | |
| Modelica.Units.SI.MassFlowRate | err_m_flow | Integration error for m_flow | |
| Real | err_der_m_flow | Integration error for der_m_flow |
Revisions
-
October 22, 2026, by Martin Sjölund:
First implementation.
This is for Buildings, #4798.