Problem 13 Consider air entering a heated duct at P₁ = 1 atm and T₁ = 288 K. Ignore th effect of friction. Calculate the amount of heat per unit mass (in joules po kilogram) necessary to choke the flow at the exit of the duct. as well as th pressure and temperature at the duct exit, for an inlet Mach number of (a) M1 = 2.0 (b) M1 = 0.2 Problem 14 The stagnation chamber of a wind tunnel is connected to a high-pressure a bottle farm which is outside the laboratory building. The two are connecte by a long pipe of 4-in inside diameter. If the static pressure ratio between th bottle farm and the stagnation chamber is 10. and the bottle-farm stat pressure is 100 atm. how long can the pipe be without choking? Assum adiabatic, subsonic, one-dimensional flow with a friction coefficient of 0.005. Problem 15 At the inlet to the combustor of a supersonic combustion ramjet (SCRAMje the flow Mach number is supersonic. For a fuel-air ratio (by mass) of 0.03 ar exit temperature of 4800°R. calculate the inlet Mach numb a combustor will be unchoked. Assume one-dimensional frictionle above which the flow flow with k=1.4, with the heat release per slug of fuel equal to 4.5 x 108 ft-lb.