A turbojet unit is flying at a speed of 268 m/s at an altitude where the ambient conditions are 0.20 bar and 220 K. The air enters an ideal diffuser and leaves the combustor at 1350 K and 1 bar. The fuel supplied has a heating value of 43,000 kJ/kg. Assume all compression and expansion processes to be isentropic. Determine (i) the air-fuel ratio (ii) the specific thrust and (iii) the propulsive efficiency.
Take cp and g for the compression process 1.005 kJ/kg K and 1.4 and for combustion and expansion processes 1.102 kJ/kg K and 1.33 respectively.