Analysis of Turbojet Engine

[mslodyczka]

I have to derive an equation that determines the stagnation temperature at the turbine inlet for a turbofan engine, from some data that was measured during an experiment.

The data I have:

engine RPM
Exhaust stagnation temperature
fuel consumption
thrust
To=16C
Po=101kPa


I have done through a fair few derivations, but keep coming up with an equation that has a mass flow rate term. Of course, this isn't included in my data.

Is there a way to work out the mass flow rate using only the information I have been given? Do I even need the mass flow rate, or is there a simpler way to work things out?

Cheers.

 

[minger]

Hmmm, that seems very tricky. What is the difference between the stagnation temperature at the turbine inlet nozzle and the exhaust cone? The only work being done (assuming adiabatic) would be the work extracted by the turbine.

That work goes into turbing the shaft, which would be accounted for by the RPM value. However, without a moment of inertia, I'm not sure you can get work done...

Hmmm...I think you may need an additional piece of information.

 

[Mene]

Hello there,

I would like to provide some insights on your analysis of the turbojet engine and the derivation of an equation for determining the stagnation temperature at the turbine inlet for a turbofan engine.

Firstly, it is important to note that the mass flow rate is a crucial parameter in determining the stagnation temperature at the turbine inlet. In fact, the equation for calculating the stagnation temperature involves the mass flow rate, specific heat ratio, and the total temperature at the compressor inlet.

However, from the data you have provided, there is a way to work out the mass flow rate without explicitly having it as one of the measured parameters. This can be done by using the thrust equation, which relates the mass flow rate, exhaust velocity, and thrust. By rearranging this equation, you can solve for the mass flow rate and use it in your derivation.

Additionally, it is also important to consider the efficiency of the engine in your analysis. The actual temperature at the turbine inlet may differ from the calculated stagnation temperature due to losses in the engine. Therefore, it is recommended to also account for the efficiency in your equation.

In terms of simplifying your analysis, you can also consider using the isentropic relations for the compressor and turbine, as they relate the stagnation temperature and pressure at different stages of the engine.

I hope this helps in your analysis and derivation. Best of luck!