Aconverging-diverging nozzle is designed to produce a mach number of 2.5 with air. a) what operating pressure ratio (preceiver/ptotal) will cause this nozzle to operate at the first, second, and third critical points? b) if the inlet stagnation pressure is 150 psia, what receiver pressures that represent the operation at these three critical points?

Air enters a horizontal, constant-diameter heating duct operating at steady state at 290 k, 1 bar, with a volumetric flow rate of 0.25 m°/s, and exits at 325 k, 0.95 bar. the flow area is 0.04 m2. assuming the ideal gas model with k = 1.4 for the air, determine (a) the velocity at the inlet and exit, each in m/s, and (c) the rate of heat transfer, in kw flow rate, in kg/s, (b) the mass kg 0.3