- #1

andymarra

- 3

- 0

**A single spool, axial flow turbojet propels an aircraft at a cruise Mach number of 1.8 at**

an altitude where the ambient pressure and temperature are 0.116 bar and 216K. The air

mass flow rate through the gas turbine is 20kgs−1, the rate of fuel consumption is 0.2kgs−1

and auxiliary devices take 100kW of power from the turbine. The compressor pressure

ratio is 3.0. The turbojet has component isentropic efficiencies as follows: intake, 0.92;

compressor, 0.93; turbine, 0.94; nozzle, 0.97. Determine the following:

an altitude where the ambient pressure and temperature are 0.116 bar and 216K. The air

mass flow rate through the gas turbine is 20kgs−1, the rate of fuel consumption is 0.2kgs−1

and auxiliary devices take 100kW of power from the turbine. The compressor pressure

ratio is 3.0. The turbojet has component isentropic efficiencies as follows: intake, 0.92;

compressor, 0.93; turbine, 0.94; nozzle, 0.97. Determine the following:

i) Flight speed in ms−1;

*(answer Ua = 530ms−1)*

ii) Compressor entry temperature and intake pressure ratio;

*(answers T2 = 356K, p2/p1= 5.138)*

iii) Compressor power;

*(answer 2.83MW)*

iv)

__Turbine inlet temperature, and the turbine pressure ratio__;

*(answers T4 = 923K, p4/p5= 1.915)*

Its the turbine inlet temp that I can't work out, i can work out the first parts fine. Basically, I am unsure of how to work out T4 by using the information given in the question.

Any help appreciated!

Regards, Andy