1. A non-afterburning turbojet is being designed for operation at an altitude of 15 km and a Mach number of 1.8. The maximum stagnation temperature at the inlet of the turbine is 1500 K. The fuel is a jet fuel having a LHV of 43124 kJ/kg and fst is 0.06. The following efficiencies apply at this Mach number: nd = 0.9 nc = 0.9 nb = 0.98 rb = 0.97 nt = 0.92 Vn = 0.98 Use a gamma value of 1.4 up to the burner, and a value of 1.3 for the rest of the engine. Assume R is 0.287 kJ/kgK throughout the engine. Plot the specific thrust, TSFC, th, np and no as a function of rc, the total pressure ratio across the compressor. Is there an optimum rc that minimizes TSFC? Is there an optimum rc that maximizes specific thrust? Consider a range of rc from 2 to 60. Assume the exhaust is ideally expanded. Also plot the nozzle area ratio as a function of r.

Fig: 1