Where necessary, assume air as an ideal gas and consider R = 287 J/(kg.K), Cp = 1005 J/(kg.K), Cv = 718 J/(kg.K). a) A nozzle is a device that is used to increase the velocity of a fluid by varying...

Where necessary, assume air as an ideal gas and consider R = 287
J/(kg.K), Cp = 1005 J/(kg.K), Cv = 718 J/(kg.K).

a)

A nozzle is a device that is used to increase the velocity of a fluid
by varying the cross-sectional area. At the last section of a jet
engine, air with a mass flow rate of 50 kg/s at
a pressure of 500 kPa and a temperature of 600 K enters a nozzle
with an inlet cross-sectional area of 5m2
. The exit area of the
nozzle is 20% of its inlet area. The air leaves the nozzle at a
velocity of 300 m/s. The nozzle is not well-insulated and during
this process, 5 kJ/kg heat is lost.

(i) In analysing this nozzle using the 1st law of thermodynamics,
the change in which type of energy is negligible?

(ii) Determine the density and velocity of the air entering the
nozzle.
(iii) Calculate the density of the air as it leaves the nozzle.


(iv) Determine the temperature of the air as it leaves the nozzle.


(v) Calculate the pressure of the air as it leaves the nozzle.