Air enters the diffuser of a ramjet engine (Fig. 9.27c) at

Chapter 9, Problem 9.90

(choose chapter or problem)

Air enters the diffuser of a ramjet engine (Fig. 9.27c) at \(6 \mathrm{lbf} / \mathrm{in}^{2}\), \(420^{\circ} \mathrm{R}\), with a velocity of 1600 ft/s, and decelerates essentially to zero velocity. After combustion, the gases reach a temperature of \(2200^{\circ} \mathrm{R}\) before being discharged through the nozzle at \(6 \mathrm{lbf} / \mathrm{in}^{2}\) On the basis of an air- standard analysis, determine

(a) the pressure at the diffuser exit, in \(\text { lbf/in. }{ }^{2}\)

(b) the velocity at the nozzle exit, in ft/s.

Neglect kinetic energy except at the diffuser inlet and the nozzle exit. Assume combustion occurs at constant pressure and flow through the diffuser and nozzle is isentropic.