UNIFIED ENGINEERING Fall 2004

Ian A. Waitz

Problem T11 (Unified Thermodynamics)

Consider a commercial airliner flying at M=0.8 at 11km (T_atm = 217K, p_atm = 22.6kPa, g = 1.4).

a) In the reference frame of the airplane, what are the static and stagnation (or total) temperatures, and static and stagnation (or total) pressures?

b) In the inlet of the engine, the flow is decelerated (adiabatically and quasi-statically) to about M=0.5 before passing into the compressor. Again in the reference frame of the airplane, what are the stagnation and static pressures and temperatures at the entrance to the compressor?

c) The compressor operates quasi-statically and adiabatically and increases the total pressure of the flow by a factor of 40, before delivering it to the combustor at a Mach number near zero (M= 0.03). What are the stagnation and static pressures and temperatures at the combustor inlet.

d) If the airliner were a supersonic transport flying at M=3 at 18km (T_atm = 217K, p_atm = 7.5kPa, g = 1.4), what are the static and stagnation temperatures, and static and stagnation pressures in the reference frame of the aircraft?

e) What pressure ratio would be required for the compressor on the supersonic aircraft if the stagnation temperatures at the exit of the compressor were constrained by material limitations to be the same as those for the subsonic aircraft?