The inlet ducting to a jet engine forms a diffuser that steadily decelerates the

Question

         The inlet ducting to a jet engine forms a diffuser that steadily decelerates the entering air to zero velocity relative to the engine before the air enters the compressor. Consider a jet airplane flying at 1000 km/h where the local atmospheric pressure is 0.6 bar and the air termperature is 8 degrees Celcius. Assuming ideal gas behavior and neglecting heat transfer and potential enregy effects, determine the temperature, in degrees Celsius, of the air entering the compressor.

I'm not even entirely sure how to begin the solution. If you could show your work, it would be sincerely appreciated,

Explanation / Answer

for diffuser

h1 + v1^2/2 = h2 + v2^2/2 ----------------(1)

where h1 h2 are specific heats per mass

zero velocity occurs at compressor entry

take v2 =0

eqn(1) becomes

H1 + 0.5*(1000*5/18 m/s) = H2 --------------(2)

from gas tables h1 cab be found at temp 1000k

SO H2 CAN BE calculated using eqn (2)

corresponding to H2 we can find temp using gas table

so T2 CAN BE KNOWN

P1 / T1 = P2/ T2 ----------------(AS VOLUME DOESN'T CHANGE)

P1 =0.6

T1= 273+8 =281 K

T2 CAN BE KNOWN FROM H2 (FROM GAS TABLE)

HENCE P2 CAN BE FOUND OUT

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