modelGTunit
Gas Turbine
Extends from BaseClasses.GTunitExhaustBase (Adds computation of exhaust composition to GTunitBase).
Information
This model adds the performance characteristics to the GTunit_base model, by means of 2D interpolation tables.Unit performance is a function of two referred quantities, i.e. Zero Loss Power Output referred at ISO conditions (ZLPout_ISO) and referred speed. In typical performance charts, curves corresponding to different referred speeds are labelled by synchronous temperatures (Tsync), i.e. inlet temperatures which would give the same referred speed if the unit operated at nominal rotational speed. The performance is thus specified by three functions[1]:
- HI_ISO = f(ZLPout_ISO, Tsync)
- PR = g(ZLPout_ISO, Tsync)
- wia_ISO = h(ZLPout_ISO, Tsync)
which in turn are specified by three tables, in the format of Modelica.Blocks.Tables.CombiTable2D:
- tableHI, where ZLPout_ISO is the first column and Tsync the first row
- tablePR, where ZLPout_ISO is the first column and Tsync the first row
- tableW, where ZLPout_ISO is the first column and Tsync the first row , respectively.
Modelling options
The packages Medium are redeclared and a mass balance determines the composition of the outgoing gas.The following options are available to select the way of definition of the table:
- Table = 0: the table is explicitly supplied as matrix parameter.
- Table = 1: the table is read from a file; the string fileName contains the path to the files where tables are stored, either in ASCII or Matlab binary format.
References:
- P. P. Walsh, P. Fletcher: Gas Turbine Performance, 2nd ed., Oxford, Blackwell, 2004, pp. 646.
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Exhaust.AbsolutePressure | pnom (from GTunitBase) | 1.013e5 | ISO reference pressure |
| Air.Temperature | Tnom (from GTunitBase) | 288.15 | ISO reference temperature |
| SI.SpecificEnthalpy | HH (from GTunitBase) | Lower Heating value | |
| SI.PerUnit | eta_mech (from GTunitBase) | 0.95 | mechanical efficiency |
| Boolean | allowFlowReversal (from GTunitBase) | system.allowFlowReversal | = true to allow flow reversal, false restricts to design direction |
| Boolean | constantCompositionExhaust (from GTunitExhaustBase) | false | Assume exhaust composition equal to reference_X |
| SI.AngularVelocity | omega_sync | 314 | synchronous value of the shaft speed |
| Real[:,:] | tableHI | fill(0, 0, 2) | Table for HI_ISO=f(ZLPout_ISO, Tsync) |
| Real[:,:] | tablePR | fill(0, 0, 2) | Table for PR=g(ZLPout_ISO,Tsync) |
| Real[:,:] | tableW | fill(0, 0, 2) | Table for wia_ISO=h(ZLPout_ISO,Tsync) |
| String | fileName | "noName" | File where matrix is stored |
| TableTypes | Table | TableTypes.matrix | Selection of the way of definition of table matrix |
| Initialisation | |||
| Modelica.SIunits.Pressure | pstart (from GTunitBase) | start pressure value | |
| Exhaust.Temperature | Tstart (from GTunitBase) | start temperature value | |
| Modelica.SIunits.MassFraction[Air.nX] | Xstart (from GTunitBase) | Air.reference_X | start gas composition |
Connectors
| Type | Name | Default | Description |
|---|---|---|---|
| FlangeA | Air_in (from GTunitBase) | ||
| FlangeA | Fuel_in (from GTunitBase) | ||
| FlangeB | FlueGas_out (from GTunitBase) | ||
| Modelica.Mechanics.Rotational.Interfaces.Flange_b | shaft_b (from GTunitBase) |
Components
| Type | Name | Default | Description |
|---|---|---|---|
| ThermoPower.System | system (from GTunitBase) | System wide properties | |
| Air.BaseProperties | gas (from GTunitBase) | ||
| Air.MassFlowRate | wia (from GTunitBase) | Air mass flow | |
| Air.MassFlowRate | wia_ISO (from GTunitBase) | Air mass flow, referred to ISO conditions | |
| Fuel.MassFlowRate | wif (from GTunitBase) | Fuel mass flow | |
| Exhaust.MassFlowRate | wout (from GTunitBase) | FlueGas mass flow | |
| Air.SpecificEnthalpy | hia (from GTunitBase) | Air specific enthalpy | |
| Fuel.SpecificEnthalpy | hif (from GTunitBase) | Fuel specific enthalpy | |
| Exhaust.SpecificEnthalpy | hout (from GTunitBase) | FlueGas specific enthalpy | |
| SI.Angle | phi (from GTunitBase) | shaft rotation angle | |
| SI.Torque | tau (from GTunitBase) | net torque acting on the turbine | |
| SI.AngularVelocity | omega (from GTunitBase) | shaft angular velocity | |
| SI.Power | ZLPout (from GTunitBase) | zero_loss power output | |
| SI.Power | ZLPout_ISO (from GTunitBase) | zero_loss power output, referred to ISO conditions | |
| SI.Power | Pout (from GTunitBase) | Net power output | |
| SI.Power | HI (from GTunitBase) | Heat input | |
| SI.Power | HI_ISO (from GTunitBase) | Heat input, referred to ISO conditions | |
| SI.PerUnit | PR (from GTunitBase) | pressure ratio | |
| Exhaust.AbsolutePressure | pc (from GTunitBase) | combustion pressure | |
| Air.AbsolutePressure | pin (from GTunitBase) | inlet pressure | |
| Real | wcomb (from GTunitExhaustBase) | Molar Combustion rate (CH4) | |
| Real | lambda (from GTunitExhaustBase) | Stoichiometric ratio (>1 if air flow is greater than stoichiometric) | |
| Modelica.Blocks.Tables.CombiTable2D | PowerOut | ||
| Modelica.Blocks.Tables.CombiTable2D | PressRatio | ||
| Modelica.Blocks.Tables.CombiTable2D | MassFlowRate | ||
| SI.Temperature | Tsync | temperature corresponding to omega referred in synchronous conditions |
Revisions
- 7 Jun 2005
by Francesco Casella:
Model restructured by inheritance. - 19 Apr 2005
by Francesco Casella:
GT unit model restructured using inheritance.
First release.