modelHEXsimple
Generic base for heat exchanger. Calculates pressure drop. Defines main variables
Extends from FreeFluids.Interfaces.TwoFluidPorts (To be used by equipment with two fluid ports.).
Information
A very simple, and undefined, heat exchanger.For the pressure drop you can consider it constant or variable with the flow.
Regarding heat transfer, you just have to supply the global heat transfer coefficient and the surface (or the power) of the exchanger, plus the inlet and outlet temperatures for the medium at the other side of the exchanger. The heat exchanged is calculated using the plain LMTD.
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 | useFixedDiffP | true | if true fixed dP will be used. Otherwise a function of mass flow rate |
| Modelica.Units.SI.PressureDifference | dP | pressure loss, constant or at reference flow rate. Negative if PortB.P < PortA.P | |
| Modelica.Units.SI.MassFlowRate | refG | reference mass flow rate. If useFixedDiffP is false | |
| Boolean | isLaminarFlow | false | flow regime to apply. Only if useFixedDiffP is false |
| Heat transfer | |||
| Modelica.Units.SI.CoefficientOfHeatTransfer | u | global heat transfer coefficient | |
| Boolean | fixSurface | true | if true, please fix the surface. If false, fix the power |
| Modelica.Units.SI.Area | s | 0 | fixed heat exchange surface |
| Modelica.Units.SI.Power | w | fixed heat transfer power. Positive if fluid inputs heat | |
| Modelica.Units.SI.SpecificHeatCapacity | extCp | 1003 | fixed specific heat capacity of external media. Air=1003. Water=4194 |
| Modelica.Units.SI.Temperature | extTin | 298.15 | fixed external media inlet temperature |
| Boolean | fixExternalFlow | false | if false, the external media outlet temp. must be given. If true, the external flow. |
| Modelica.Units.SI.MassFlowRate | extG | fixed external media massic flow | |
| Modelica.Units.SI.Temperature | extTout | 318.15 | fixed external media outlet temperature |
| Boolean | counterCurrentFlow | true | if false, concurrent flow is considered |
Connectors
| Type | Name | Default | Description |
|---|---|---|---|
| FreeFluids.Interfaces.FluidPortA | PortA (from TwoFluidPorts) | ||
| FreeFluids.Interfaces.FluidPortB | PortB (from TwoFluidPorts) |
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.TemperatureDifference | LMTD | ||
| Modelica.Units.SI.Area | S | ||
| Modelica.Units.SI.MassFlowRate | Gext | external media mass flow rate | |
| Modelica.Units.SI.Temperature | TextOut | ||
| Modelica.Units.SI.ThermalConductance | ThConductance | W/K | |
| Modelica.Units.SI.Power | W | heat transfer. Positive if fluid inputs heat | |
| Medium.ThermodynamicState | StateA | state at PortA | |
| Medium.ThermodynamicState | StateB | state at PortB | |
| Medium.Temperature | Ta | ||
| Medium.Temperature | Tb |