# Homework Help: University Thermodynamics- Turbojet

1. Jul 27, 2010

### andymarra

Hello, I am currently revising for a thermodynamics resit exam and I cannot get past a certain part in a turbojet question from a past paper. This is the past paper which I failed a few months ago and still cant understand it. Any help would be appreciated.

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:

i) Flight speed in ms−1;
ii) Compressor entry temperature and intake pressure ratio;
(answers T2 = 356K, p2/p1= 5.138)
iii) Compressor power;