modelPumpBase
Extends from Interfaces.TwoFluidPorts (To be used by equipment with two fluid ports.).
Information
Its function is to define the common elements needed for different type of pumps, providing just few equations between them.
Parameters:
- forceSpeed=false. If made true, the pump speed will be made equal to the manual defined parameter, or to the speed received via a connector, depending on the selection made.
- useExternalSpeed=false. If made true, the speed received at the connector is used. Otherwise the manually filled parameter will be used. (the forceSpeed parameter must be true for calculation to apply).
- fixedSpeed. The manually fixed speed request.
- numParallelUnits=1. The number of identical pumps working in parallel.
- directFlow=true. If true, the flow will be from port A to port B. And the reverse if false.
Variables:
- N. for the pump speed. In order to assign it, a conditional RealInput connector 'Speed' connected to a protected RealInput connector 'SpeedIn' are used. I 'useExternalSpeed' is false the 'Speed' connector and its connection disappears, and N is made equal to 'fixedSpeed'.
- Qunit and Qtotal. For the volumetric flow of each individual pump, and of all parallel pumps. They are related by Qtotal = Qunit * numParallelUnits. And Qtotal is related to the mass flow by PortA.G = Qtotal * Rho.
- A ThermodynamicState 'State' is defined in order to gate the physical properties of the fluid. The state is defined at the enthalpy and pressure of PortA, as we do not expect too much change for the physical properties between the ports.
- The variables Rho and T, get the density and the temperature of the State.
- The variables specific energy: 'SE', pump efficiency: 'Efficiency', total absorbed power: 'Wabs'. Two equations are provided here, one comes from the definition of efficiency, and the other relates 'Wabs' with flow, differential pressure and efficiency.
- A pump impulsion height variable 'Dh' that express the differential pressure between ports a liquid height. An equation relating Dh with the differential pressure and density is given.
An equation is missing for finding Efficiency, and it is missing also an equation relating N, Qunit and Dh.
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Ports links | |||
| Boolean | useElevDifference (from TwoFluidPorts) | true | introduces, or not, an equation for the ports elevation. Use only in one connector |
| FreeFluids.Types.ElevationOption | elevCalcMethod (from TwoFluidPorts) | FreeFluids.Types.ElevationOption.differential | if useElevDifference==true, selects the equation to use: differential, or absolute for PortB |
| Modelica.Units.SI.Length | elevDifference (from TwoFluidPorts) | 0.0 | used only if previously selected. Positive if PortB higher than PortA |
| Modelica.Units.SI.Length | portBelevation (from TwoFluidPorts) | 0.0 | used only if previously selected. |
| Boolean | calcEnthalpyDifference (from TwoFluidPorts) | true | if true, will calculate the enthalpy difference between ports. Use only in one connector |
| Boolean | passComposition (from TwoFluidPorts) | true | if true, the equation PortA.X=PortB.X will be activated |
| Flow | |||
| Boolean | forceSpeed | false | if true, the internal, or external, speed will be applied |
| Boolean | useExternalSpeed | false | If true, the connector speed will be used |
| Modelica.Units.SI.Frequency | fixedSpeed | 2900.0/60.0 | internally fixed speed for the pump |
| Integer | numParallelUnits | 1 | |
| Boolean | directFlow | true | if false, reverse flow |
| User phys. prop. | |||
| Modelica.Units.SI.Density | rho | 0 | fixed average density to use in calculations |
Connectors
| Type | Name | Default | Description |
|---|---|---|---|
| FreeFluids.Interfaces.FluidPortA | PortA (from TwoFluidPorts) | ||
| FreeFluids.Interfaces.FluidPortB | PortB (from TwoFluidPorts) | ||
| Modelica.Blocks.Interfaces.RealInput | Speed | ||
| FreeFluids.Various.TemperatureOutput | Ta |
Components
| Type | Name | Default | Description |
|---|---|---|---|
| Modelica.Units.SI.SpecificEnthalpy | Hdiff (from TwoFluidPorts) | specific enthalpy difference: Port B - Port A | |
| Modelica.Units.SI.PressureDifference | Pdiff (from TwoFluidPorts) | pressure difference: Port B - Port A | |
| Modelica.Units.SI.Frequency | N | Rotational speed in 1/s | |
| Real | Efficiency | efficiency | |
| Modelica.Units.SI.Power | Wabs | total absorbed power | |
| Modelica.Units.SI.SpecificEnergy | SE | ||
| Modelica.Units.SI.VolumeFlowRate | Qunit | ||
| Modelica.Units.SI.VolumeFlowRate | Qtotal | ||
| Medium.ThermodynamicState | State | ||
| Modelica.Units.SI.Density | Rho | ||
| Medium.Temperature | T | Temperature at PortA | |
| Modelica.Units.SI.Height | Dh | differential pressure as liquid height |