modelCombustionChamberBase
Extends from Icons.Gas.Mixer.
Information
This is the model-base of a Combustion Chamber, with a constant volume.The metal wall temperature and the heat transfer coefficient between the wall and the fluid are uniform. The wall is thermally insulated from the outside. It has been assumed that inlet gases are premixed before entering in the volume.
Modelling options
This model has three different Medium models to characterize the inlet air, fuel, and flue gas exhaust.
If gamma = 0, the thermal effects of the surrounding walls are neglected.
There are two ways to obtain correct energy balances. The first is to explicitly set the lower heating value of the fuel HH, and use medium models that do not include the enthalpy of formation, by setting excludeEnthalpyOfFormation = true, which is the default option in Modelica.Media. As the heating value is usually provided at 25 degC temperature, it is also necessary to set referenceChoice =ReferenceEnthalpy.ZeroAt25C in all medium models for consistency. This is done in the medium models contained within ThermoPower.Media.
Alternatively, one can set excludeEnthalpyOfFormation = false in all media and set HH = 0. By doing so, the heating value is automatically accounted for by the difference in the enthalpy of formation.
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| SI.Volume | V | Inner volume | |
| SI.Area | S | 0 | Inner surface |
| SI.CoefficientOfHeatTransfer | gamma | 0 | Heat Transfer Coefficient |
| SI.HeatCapacity | Cm | 0 | Metal Heat Capacity |
| SI.SpecificEnthalpy | HH | Lower Heating value of fuel | |
| Boolean | allowFlowReversal | system.allowFlowReversal | = true to allow flow reversal, false restricts to design direction |
| Initialisation | |||
| SI.Temperature | Tmstart | 300 | Metal wall start temperature |
| Air.AbsolutePressure | pstart | 101325 | Pressure start value |
| Air.Temperature | Tstart | 300 | Temperature start value |
| Air.MassFraction[Exhaust.nX] | Xstart | Exhaust.reference_X | Start flue gas composition |
| Choices.Init.Options | initOpt | system.initOpt | Initialisation option |
| Boolean | noInitialPressure | false | Remove initial equation on pressure |
Connectors
| Type | Name | Default | Description |
|---|---|---|---|
| FlangeA | ina | inlet air | |
| FlangeA | inf | inlet fuel | |
| FlangeB | out | flue gas |
Components
| Type | Name | Default | Description |
|---|---|---|---|
| ThermoPower.System | system | System wide properties | |
| Exhaust.BaseProperties | fluegas | ||
| SI.Mass | M | Gas total mass | |
| SI.Mass[Exhaust.nXi] | MX | Partial flue gas masses | |
| SI.InternalEnergy | E | Gas total energy | |
| SI.Temperature | Tm | Wall temperature | |
| Air.SpecificEnthalpy | hia | Air specific enthalpy | |
| Fuel.SpecificEnthalpy | hif | Fuel specific enthalpy | |
| Exhaust.SpecificEnthalpy | ho | Outlet specific enthalpy | |
| SI.Power | HR | Heat rate | |
| SI.Time | Tr | Residence time |
Contents
| Name | Description |
|---|---|
 Air | |
| Fuel | |
| Exhaust |
Revisions
- 30 May 2005
by Francesco Casella:
Initialisation support added. - 31 Jan 2005
by Francesco Casella:
CombustionChamber model restructured using inheritance.First release.