1. A steam power plant operates between the pressure limits of 4.5MPa and 15kPa. Steam enters the pump as saturated liquid and leaves the turbine as saturated vapor. Determine the ratio of the work delivered by the turbine to the work consumed by the pump. Assume the entire cycle to be reversible and the heat losses from the pump and the turbine to be negligible.
2. Air enters an adiabatic compressor at 120kPa and 25°C at a rate of 2.5m3 /s, and it exits at 277°C. The compressor has an isentropic efficiency of 80percent. Neglecting the changes in kinetic and potential energies, determine (a) the exit pressure of air and (b) the power required to drive the compressor.
3. Air is expanded from 1.5MPa and 177°C to 90kPa in an adiabatic turbine. Determine the isentropic efficiency of this turbine if the air is exhausted at 0°C.