Assume rayleigh line flow the combustion chamber

AE221 Gas dynamics
(2014-15, II Semester)

Tutorial – 7

3. Air enters a turbojet combustion chamber at 400 K and 200 kPa, with a temperature after combustion of 1000 K. If the heating value of the fuel is 48,000 kJ/kg, determine the required fuel-air ratio (on a mass basis). Assume Rayleigh line flow in the combustion chamber. What fuel-air ratio would be required to choke the combustion chamber? The inlet velocity is 35 m/s.

[Ans: 0.0126 and 0.2253]

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6. In the system shown in figure below, friction exists only from 2 to 3 and from 5 to 6. Heat is removed between 7 and 8. The Mach number at section 9 is unity. Draw the T-s diagram for the system, showing both the static and stagnation curves. Are points 4 and 9 on the same horizontal level?