Question

In an aircraft jet engine at takeoff, the combustion products expand adiabatically in the exhaust nozzle. At entrance to the nozzle, the pressure is 0.180 MPa and the temperature is 1200 K. The kinetic energy of the gas entering the nozzle is very much smaller than the kinetic energy of the gas leaving the nozzle. The specific heat of the exhaust gas varies with temperature approximately as follows: Cp = 0.959 + 1.16 X 10-4T + 3.65 X 10-8T2 , in which the units of cP are kJ/kg · K and Tis the temperature in K. The molecular weight of the exhaust gas is 30. Supposing the expansion to be frictionless (reversible) as well as adiabatic, show how the exhaust velocity and pressure will depend on the exhaust temperature for a series of values: 1100, 1000, and 900 K. At each temperature determine also the speed of sound VyRT'.

Answer 1

At entrance to the nozzle, the pressure is 0.180 MPa and the temperature is 1200 K. The kinetic energy of the gas entering the nozzle is very much smaller than ... The specific heat of the exhaust gas varies with temperature approximately as follows: ... Problem 4P: In an aircraft jet engine at takeoff, the combustion product.