.ThermoSysPro.FlueGases.Machines.CombustionTurbine

Information

## Copyright © EDF 2002 - 2026  
## ThermoSysPro Version 4.2  
This component model is documented in Sect. 11.4 of the ThermoSysPro book.   

# Combustion turbine   

A combustion turbine, also called gas turbine, is a type of internal combustion engine. The main elements common to all gas turbines are an upstream rotating gas compressor, a combustor and a downstream turbine on the same shaft as the compressor.  
In this model, the hot fluid flow is assumed steady-state and supersonic.  

## Modelica component model  

The equations mentioned below are implemented in the component *CombustionTurbine*, located in the *FlueGases.Machines* sub-library.  
The component has 4 connectors:  
- Ce: flue gases at the inlet,  
- Cs: flue gases at the outlet,  
- CompressorPower: compressor power input,  
- MechPower: mechanical power output.  
   
![modelica://ThermoSysPro/UsersGuide/Documentation/ThermoSysPro.FlueGases.Machines.CombustionTurbine.svg](modelica://ThermoSysPro/UsersGuide/Documentation/ThermoSysPro.FlueGases.Machines.CombustionTurbine.svg)  

## Nomenclature  

| Symbol| Description| Unit| Definition| Modelica name|  
| :------------------------- | :----------------------------------------------------- | :--------------------------- | :---------------------------------- | :-------------------------------|  
| \\(h\_{\mathrm{i}}\\)| Fluid specific enthalpy at the inlet| \\(\mathrm{J} / \mathrm{kg}\\) ||He|  
| \\(h\_{\mathrm{is}}\\)| Fluid specific enthalpy after the isentropic expansion | \\(\mathrm{J} / \mathrm{kg}\\) ||His|  
| \\(h\_{\mathrm{o}}\\)| Fluid specific enthalpy at the outlet| \\(\mathrm{J} / \mathrm{kg}\\) ||Hs|  
| \\(\dot{m}\\)| Fluid mass flow rate| \\(\mathrm{kg} / \mathrm{s}\\) ||Q|  
| \\(\dot{m}\_{\mathrm{cor}}\\) | Corrected mass flow rate \(mass flow rate parameter\)| \\(-\\)||Qred|  
| \\(P\_{\mathrm{i}}\\)| Fluid pressure at the inlet| \\(\mathrm{Pa}\\)||Pe|  
| \\(P\_{\mathrm{o}}\\)| Fluid pressure at the outlet| \\(\mathrm{Pa}\\)||Ps|  
| \\(W\_{\mathrm{c}}\\)| Compressor power \(negative value\)| \\(\mathrm{W}\\)||Wcp|  
| \\(W\_{\mathrm{m}}\\)| Mechanical power| \\(\mathrm{W}\\)||Wmech|  
| \\(W\_{\mathrm{t}}\\)| Turbine power \(total power\)| \\(\mathrm{W}\\)||Wturb|  
| \\(X\\)| Ratio between the actual and nominal expansion rate| \\(-\\)| \\(\pi / \pi\_{n}\\)|Xtau|  
| \\(\eta\_{\mathrm{is}}\\)| Isentropic efficiency| \\(-\\)||is_eff|  
| \\(\eta\_{\mathrm{n}}\\)| Nominal isentropic efficiency| \\(-\\)||is_eff_n|  
| \\(\pi\\)| Expansion rate| \\(-\\)| \\(P\_{\mathrm{o}} / P\_{\mathrm{i}}\\)|tau|  
| \\(\pi\_{\mathrm{n}}\\)| Nominal expansion rate| \\(-\\)||tau_n|  

## Governing equations  

### Fluid specific enthalpy at the outlet  


    
    

- Validity domain:   
   
 \\(\forall h\_{\mathrm{i}}\\)  

- Mathematical formulation:   
   
 $$h\_{\mathrm{o}}=h\_{\mathrm{i}}+\eta\_{\mathrm{is}} \cdot\left\(h\_{\mathrm{is}}-h\_{\mathrm{i}}\right\)$$  

- Comments:   
   



### Isentropic efficiency  


    
    

- Validity domain:   
   
 \\(X>0\\)  

- Mathematical formulation:   
   
 $$\eta\_{\mathrm{is}}=f\_{\eta\_{\mathrm{is}}}\(X\) \cdot \eta\_{n}$$  

- Comments:   
   
 \\(f\_{\eta\_{\mathrm{is}}}\(X\)\\) is the turbine map expressed as a polynomial function of \\(X\\).   


### Total turbine power  


    
    

- Validity domain:   
   
 \\(\forall \dot{m}\\)  

- Mathematical formulation:   
   
 $$W\_{\mathrm{t}}=\dot{m} \cdot\left\(h\_{\mathrm{i}}-h\_{\mathrm{o}}\right\)$$  

- Comments:   
   



### Mechanical power  


    
    

- Validity domain:   
   
 \\(\forall \dot{m}\\)  

- Mathematical formulation:   
   
 $$W\_{\mathrm{m}}=W\_{\mathrm{t}}+W\_{\mathrm{c}}$$  

- Comments:   
   
 The mechanical power produced by the shaft of the electricity generator is the total turbine power minus the power used by the compressor (counted negatively).   


### Mass flow rate  


    
    

- Validity domain:   
   
 \\(\forall P\_{i}\\) and \\(\forall T\_{\mathrm{i}}\\)  

- Mathematical formulation:   
   
 $$\dot{m}\_{\mathrm{cor}}=\frac{\dot{m} \cdot \sqrt{T\_{\mathrm{i}}}}{P\_{\mathrm{i}}}$$  

- Comments:   
   
 This equation calculates the mass flow rate from the corrected mass flow rate provided by the user.   

## References   
   
El Hefni, Baligh and Bouskela, Daniel (2019). [Modeling and Simulation of Thermal Power Plants with ThermoSysPro](https://link.springer.com/book/10.1007/978-3-030-05105-1), sect. 11.4. Springer Nature Switzerland AG.  
    

Revisions