1) Nitrogen gas flows into a convergent nozzle at a pressure of 225kPa, a temperature of 440K and with a very low inlet velocity which may be assumed to be zero. The flow is accelerated and exits the nozzle at a pressure of 100kPa and a temperature of 330K.
Assuming the nozzle is insulated, with no change in height between inlet and exit,
a) What is the change in specific enthalpy of the Nitrogen ?(kJ/kg)
b) What is the velocity of the Nitrogen at the exit of the nozzle ? (m/s)
Assume a constant specific heat of N2 at constant pressure, CpN2 = 1042 J/kg K
2) What is the thermal efficiency of a Carnot cycle heat engine operating between a hot reservoir at 350oC and a cold reservoir at 18oC?