Nitrogen (N2) at 25 bar, 450 K enters a turbine and expands to 2 bar, 250 K with a mass flow rate of 0.2 kg/s. The turbine operates at steady state with negligible heat transfer with its surroundings. Assuming the ideal gas model with k = 1.399 and ignoring the effects of motion and gravity, determine:
(a) the isentropic turbine efficiency.
(b) the exergetic turbine efficiency.
Let To = 25*C, po = 1 atm

Acompressor receives the shaft work to decrease the pressure of the fluid. a)- true b)- false

Ifa component is made of two or more materials with different modulus of elasticity (e), it is called a composite member and we calculate the factor·n". mention the formula for calculating n". also, ifn> 1, explain what will happen to the 1. transformed. gi) ifn 1, what will happen to the material when transformed material when

Awall of 0.5m thickness is to be constructed from a material which has average thermal conductivity of 1.4 w/mk. the wall is to be insulated with a material having an average thermal conductivity of 0.35 w/mk so that heat loss per square meter shall not exceed 1450 w. assume inner wall surface temperature of 1200°c and outer surface temperature of the insulation to be 15°c. calculate the thickness of insulation required.