1) Initially, an insulated rigid tank contains 3.86 kg of water at 265oC and 1 MPa. A heater in the wall of the tank maintains the wall temperature at 600oC. After a period of time, the pressure in the tank rises to 1.5 MPa. Determine the total entropy generation (kJ/K) during this process.
The following formulas will prove useful in solving this problem:
Since Tb is constant, then S2 - S1 = Q / Tb + Sgen
m*(s2 - s1) = Q / (600+273.15) + Sgen
Sgen = m*(s2 - s1) - Q / (600+273.15)
2) An adiabatic steam turbine used in a power plant to generate electrical power operates at steady state with negligible change in kinetic or potential energy. The steam at the inlet of the turbine is at 8 MPa and 525.4oC. The steam exits the turbine at 500 kPa and 180oC. Determine the rate of entropy production (kJ/kg-K) within the turbine.