Air enters the diffuser of a ramjet engine (Fig. 9.27c) at 6 lbf/in.2 , 4208R, with a velocity of 1600 ft/s, and decelerates essentially to zero velocity. After combustion, the gases reach a temperature of 22008R before being discharged through the nozzle at 6 lbf/in.2 On the basis of an airstandard analysis, determine (a) the pressure at the diffuser exit, in 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.
• SpeedingUpIndex o Somethingpersomethingelse=index o something/somethingelse=speed/time=acceleration • Tofindacceleration…(twoways) 1. DataTableWay Example: t v Δt(t 2t 1) Δv(v 2v )1 a(Δv/Δt) 0s 5mph -- -- -- 2s 25mph 2 20 10 4s 45mph 2 20 10 2. AccelerationEquation:(a)=Δv/Δt (0s,5mph) (4s,45mph) a=Δv/Δt=(45mph-5mph)/(4s-0s)=40mph/4s=10mph/s v=
