functionpressure
Pump or fan head away from the origin without correction for mover flow resistance
Extends from Modelica.Icons.Function.
Information
This function computes the fan static pressure raise as a function of volume flow rate and revolution in the form
Δp = rN2 s(V̇/rN, d),
where Δp is the pressure rise, rN is the normalized fan speed, V̇ is the volume flow rate and d are performance data for fan or pump power consumption at rN=1.
Implementation
The function s(·, ·) is a cubic hermite spline. If the data d define a monotone decreasing sequence, then s(·, d) is a monotone decreasing function.
The function allows rN to be zero.
Inputs
| Type | Name | Default | Description |
|---|---|---|---|
| Modelica.Units.SI.VolumeFlowRate | V_flow | Volumetric flow rate | |
| Real | r_N | Relative revolution, r_N=N/N_nominal | |
| Real[:] | d | Derivatives of flow rate vs. pressure at the support points | |
| Modelica.Units.SI.PressureDifference | dpMax | Maximum pressure drop at nominal speed, for regularisation | |
| Modelica.Units.SI.VolumeFlowRate | V_flow_max | Maximum flow rate at nominal speed, for regularisation | |
| BuildingSystems.Fluid.Movers.BaseClasses.Characteristics.flowParametersInternal | per | Pressure performance data |
Outputs
| Type | Name | Default | Description |
|---|---|---|---|
| Modelica.Units.SI.PressureDifference | dp | Pressure raise |
Revisions
-
September 8, 2016, by Michael Wetter and Filip Jorissen:
Changed implementation to allowr_N = 0.
This is for #458. -
September 7, 2016, by Michael Wetter:
Moved function which was a protected function to make it public, as it is now called by BuildingSystems.Fluid.Movers.BaseClasses.FlowMachineInterface.