functionpressure
Pump or fan head away from the origin without correction for mover flow resistance
Extends from Modelica.Icons.Function (Icon for functions).
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 | |
| Buildings.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 Buildings.Fluid.Movers.BaseClasses.FlowMachineInterface.