Q1. One single-shaft turbojet engine propels an aircraft which is flying at an altitude of 33,000ft and travelling at a Mach number of 0.85. At this altitude, the static temperature and static pressure are 222.82K and 26.0kPa respectively. a) Assuming no losses in the engine intake, find the stagnation temperature Toz and stagnation pressure Poz just upstream of the compressor. Adopting the approach from the recommended course text book, Cumpsty, we will assume that the normalised mass flow rate per unit area through the nozzle exit plane of the propelling nozzle and through the nozzle guide vanes upstream of the turbine are equal. As a consequence: P05 P04 (A4\7p (ke-1)-2ke -2ke == Ag/ and 27p(ke-1) T05 (A4\2ke-np (ke-1) Ag T04 = For this engine, the area ratio A4/A = 0.493, the polytropic efficiencies of the compressor and the turbine are both 0.90. Under these flight conditions, the turbine entry stagnation temperature is T04 1100K. Given that: P03 T03 ka-1 and Cpa (T03 - T02) = Cpe (T04- T05) = C KHT04 = P02 T02- b) Find P03, P04 P05, T03, T05 and KH. c) Confirm that the propelling nozzle is choked. d) Given that: -(ke+1) ke (ke + 12(ke-1) m4= ke-1 2 for when the Mach number is unity, find the mass flow rate of the exhaust gas. e) Calculate the mass flow rate of gas through the propelling nozzle for these fight conditions if the nozzle exit plane area A, of the propelling nozzle is 0.20m. For air, cp = 1.005 kJ/kg.K, R = 0.287 kJ/kg.K, k = 1.4 For exhaust gas, cp = 1.244 kJ/kg.K, R = 0.287 kJ/kg.K, k = 1.3. The following equation might be useful. P = P(1+ (1) M (1)