Problem 1) Two kilograms of an ideal gas with constant cp=1kJ/kgK and cv=0.7kJ/kgK are contained in an insulated piston-cylinder device with an initial volume of 0.3m3 and a pressure of 10bar. The piston is then allowed to move until the volume quadruples.
If the process is considered reversible, find out:
a) The temperature of the final state in K.
b) The work in kJ.
If irreversibilities during the process cause entropy to increase by 0.1kJ/K, find out:
c) The temperature of the final state in K.
d) The work in kJ.
e) Draw reversible and irreversible processes in the T-s diagram.
Problem 2)
A mass flow of 10kg/s of water vapour at 30bar and 500°C flows steadily through inlet an insulated turbine. Pressure of the water is reduced to 1bar at the turbine outlet. Neglecting kinetic and potential energy effects, find out:
a) Maximum power output in kW generated by turbine and its corresponding outlet temperature.
b) Actual power output in kW generated by turbine and its corresponding outlet temperature if its adiabatic efficiency is 90%.
c) Outline reversible and irreversible processes in the T-s diagram.