modelHeader
Header with metal walls for water/steam flows
Extends from Icons.Water.Header.
Information
This model describes a constant volume header with metal walls. The fluid can be water, steam, or a two-phase mixture.
It is possible to take into account the heat storage and transfer in the metal wall in two ways:
- Leave InternalSurface unconnected, and set the appropriate values for the total wall heat capacity Cm, surface S and heat transfer coefficient gamma. In this case, the metal wall temperature is considered as uniform, and the wall is thermally insulated from the outside.
- Set Cm = 0, and connect a suitable thermal model of the the wall to the InternalSurface connector instead. This can be useful in case a more detailed thermal model is needed, e.g. for thermal stress studies.
The model can represent an actual header when connected to the model of a bank of tubes (e.g., Flow1D with Nt>1).
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| SI.Volume | V | Inner volume | |
| SI.Area | S | 0 | Internal surface |
| SI.Position | H | 0 | Elevation of outlet over inlet |
| SI.CoefficientOfHeatTransfer | gamma | 0 | Heat Transfer Coefficient |
| SI.HeatCapacity | Cm | 0 | Metal Heat Capacity |
| Boolean | allowFlowReversal | system.allowFlowReversal | = true to allow flow reversal, false restricts to design direction |
| Initialisation | |||
| Choices.FluidPhase.FluidPhases | FluidPhaseStart | Choices.FluidPhase.FluidPhases.Liquid | Fluid phase (only for initialization!) |
| Medium.AbsolutePressure | pstart | Pressure start value | |
| Medium.SpecificEnthalpy | hstart | if FluidPhaseStart == Choices.FluidPhase.FluidPhases.Liquid then 1e5 else if FluidPhaseStart == Choices.FluidPhase.FluidPhases.Steam then 3e6 else 1e6 | Specific enthalpy start value |
| Medium.Temperature | Tmstart | 300 | Metal wall temperature start value |
| Choices.Init.Options | initOpt | system.initOpt | Initialisation option |
| Boolean | noInitialPressure | false | Remove initial equation on pressure |
| Boolean | noInitialEnthalpy | false | Remove initial equation on enthalpy |
Connectors
| Type | Name | Default | Description |
|---|---|---|---|
| FlangeA | inlet | ||
| FlangeB | outlet | ||
| Thermal.HT | thermalPort | Internal surface of metal wall |
Components
| Type | Name | Default | Description |
|---|---|---|---|
| Medium.ThermodynamicState | fluidState | Thermodynamic state of the fluid | |
| ThermoPower.System | system | System wide properties | |
| Medium.AbsolutePressure | p | Fluid pressure at the outlet | |
| Medium.SpecificEnthalpy | h | Fluid specific enthalpy | |
| Medium.SpecificEnthalpy | hi | Inlet specific enthalpy | |
| Medium.SpecificEnthalpy | ho | Outlet specific enthalpy | |
| SI.Mass | M | Fluid mass | |
| SI.Energy | E | Fluid energy | |
| Medium.Temperature | T | Fluid temperature | |
| Medium.Temperature | Tm | Wall temperature | |
| SI.Time | Tr | Residence time | |
| Real | dM_dt | ||
| Real | dE_dt |
Contents
| Name | Description |
|---|---|
 Medium |
Revisions
- 30 May 2005
by Francesco Casella:
Initialisation support added. - 12 Apr 2005
by Francesco Casella:
InternalSurface connector added. - 16 Dec 2004
by Francesco Casella:
Standard medium definition added. - 28 Jul 2004
by Francesco Casella:
Added head between inlet and outlet. - 7 Jul 2004
by Francesco Casella:
Changed name from Collector to Header. - 18 Jun 2004
by Francesco Casella:
Adapted to Modelica.Media. - 1 Oct 2003
by Francesco Casella:
First release.