Air enters the diffuser of a turbojet engine in flight at 0.82 bar, 230 K, with a mass flow rate of 68 kg/s and a velocity of 245 m/s. The compressor pressure ratio is 10. Air enters the turbine at 1250 K with the same pressure as at the exit of the compressor. Air exits the nozzle at 0.82 bar. The nozzle and the diffuser operate adiabatically and with no internal irreversibilities. The compressor and turbine operate adiabatically. The compressor has an isentropic efficiency of 87%, and the turbine has an isentropic efficiency of 90%. Potential energy effects can be neglected as can kinetic energy effects internal to the engine. On the basis of air-standard analysis, determine
(a) the rate of heat addition, in kW.
(b) the pressure at the turbine exit, in bar.
(c) the compressor power input, in kW.
(d) the velocity at the nozzle exit, in m/s.4-2. Determine the thrust, kN, for the turbojet engine of Problem 4-1.