modelValveCompressible
Control valve model for compresible liquid flow
Extends from ValvePartial (General control valve model).
Information
Extends the ValvePartial model, fixing isCompressibleFlow=true.
It adds two Medium.ThermodynamicState StateA and StateB. In order to retrieve the physical properties at both ports. It defines also variables for temperature, density and velocity at both ports: Ta, RhoA,Va, Tb, RhoB, Vb.
The State variable (used for retrieving physical properties for the pressure drop calculation) is defined at the highest enthalpy of the two ports and at the lowest pressure of the ports (but not lowest than half of the highest pressure).
An equation is added relating the two ports enthalpy calcEnthalpyDifference=true. It will take into account the kinetic energy only if the valve diameter is higher than 0.
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 | |||
| FreeFluids.Types.ValveFixOption | fix (from ValveBase) | FreeFluids.Types.ValveFixOption.fixKv | select the value to fix: Kv, pressure drop, or flow |
| Modelica.Units.SI.Area | fixedKv (from ValveBase) | 1.0 | Kv value if it is fixed |
| Modelica.Units.SI.PressureDifference | fixedDP (from ValveBase) | -0.5e5 | negative if PortB.P<PortA.P |
| Modelica.Units.SI.MassFlowRate | fixedFlow (from ValveBase) | 1.0 | fixed mass flow to maintain at Port A. Possitive if flow is in |
| Boolean | isCompressibleFlow (from ValvePartial) | false | if compressible, it will be treated always as adiabatic |
| Boolean | isLinear (from ValvePartial) | true | If true, linear characteristic is applied, otherwise isoporcentual |
| Boolean | useFixedAperture (from ValvePartial) | true | if true the aperture parameter is used. Otherwise aperture is supplied by the connector |
| Real | aperture (from ValvePartial) | 1.0 | maximum just 1 valve should be closed (aperture=0) in a line |
| Physical data | |||
| SI.Length | di | 0.0 | if >0, kinetic energy is taken into account |
Connectors
| Type | Name | Default | Description |
|---|---|---|---|
| FreeFluids.Interfaces.FluidPortA | PortA (from TwoFluidPorts) | ||
| FreeFluids.Interfaces.FluidPortB | PortB (from TwoFluidPorts) | ||
| Modelica.Blocks.Interfaces.RealInput | Opening (from ValvePartial) |
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.Area | Kv (from ValveBase) | ||
| Modelica.Units.SI.Area | Cv (from ValveBase) | ||
| Modelica.Units.SI.VolumeFlowRate | Q (from ValveBase) | ||
| Medium.ThermodynamicState | State (from ValveBase) | ||
| Medium.Density | Rho (from ValveBase) | ||
| Medium.Temperature | T (from ValveBase) | Temperature | |
| SI.Area | KvFlow (from ValvePartial) | Kv at actual aperture | |
| Medium.ThermodynamicState | StateA | thermodynamic state at PortA | |
| Medium.ThermodynamicState | StateB | thermodynamic state at PortB | |
| Medium.Density | RhoA | density at PortA | |
| Medium.Density | RhoB | density at PortB | |
| Modelica.Units.SI.Velocity | Va | ||
| Modelica.Units.SI.Velocity | Vb | ||
| Medium.Temperature | Ta | Temperature at PortA | |
| Medium.Temperature | Tb | Temperature at PortB |