For the following questions answer them individually
A two stage centrifugal compressor operating at 3000 rpm is to compress refrigerant R134a from an evaporator temperature of $$O^\circ C (h_i = 398.6 kJ/kg)$$ to a condensing temperature of $$32^\circ C (h_e = 419.8 kJ/kg)$$. If the impeller diameter of both the stages have to be same, what is the diameter of the impeller?
Assume suction condition to be dry saturated, compression process isentropic, impeller blades radial and refrigerant enters impeller radially
Consider a simple gas turbine (Brayton cycle) and a gas turbine with perfect regeneration. In both the cycles, the pressure ratio is 8 and the ratio of specific heats of working medium is 1.5. The ratio of minimum to maximum temperatureis 0.2 (with temperature in K) in the regenerative cycle. The ratio of the thermal efficiency of the simple cycle to that of tpseneralive cycle is