Texts: Solve Aerodynamic Question 1 [40 MARKS] A static engine test is conducted on a new single-shaft turbojet. The ambient static pressure is 101.8 kPa. Assume perfect gas with specific heat at constant pressure for air, Cpair is 1.005 kJ/(kg K), and the specific heat at constant pressure for combustion gas, Cp(comb) is 1.147 kJ/(kg K). You may assume the specific gas constant, R, is 287.05 J/(kg K) for air as well as for combustion gas.

1. The intake air mass flow rate is 50 kg/s. The inlet burner temperature is 800 K, and the exit burner temperature is 1,600 K. Find the fuel mass flow rate. You should use the FAR chart which can be found at the end of the exam paper. [4 MARKS]
2. The turbine generates 25 MW of power, and the adiabatic efficiency of the turbine is 90%. Calculate the turbine pressure drop ratio (outlet pressure to inlet pressure). Assume there is no blade cooling bleed, but do not neglect the fuel mass flow rate. [9 MARKS]
3. The stagnation pressure at the turbine inlet is 850 kPa, and the pressure loss in the exhaust jet pipe is 5%. If the flow in the nozzle is choked, calculate the static pressure at the nozzle throat. [7 MARKS]
4. Calculate the nozzle exit velocity. [5 MARKS]
5. Calculate the nozzle exit flow area and the nozzle exit geometric area. The nozzle discharge coefficient is 0.97. [9 MARKS]
6. Calculate the gross thrust, ram drag, and net thrust of the turbojet engine. Assume the nozzle velocity coefficient is 1. [6 MARKS]

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