Q1.
(a) A system is taken through a thermodynamic cycle consisting of three processes. Process 1-2 is an isobaric compression, process 2-3 is an isothermal expansion, and process 3-1 is an isochoric heating. The system is a gas with constant specific heats. The initial state is p1 = 200 kPa, T1 = 300 K and V1 = 0.5 m3. The final volume in process 1-2 is V2 = 0.2 m3. The temperature in process 2-3 is T2 = 400 K. The heat added to the system during process 3-1 is Q_{31} = 100 kJ. Determine the net work done by the system during the cycle.
(b)
A steady-flow energy equation for a control volume is given by:
dot{Q} - dot{W} = sum_{out} dot{m} left( h + rac{V2}{2} + gz ight) - sum_{in} dot{m} left( h + rac{V2}{2} + gz ight)
Consider a turbine with steam entering at p1 = 4 MPa, T1 = 400^circC, V1 = 80 m/s and z1 = 3 m. The steam leaves at p2 = 100 kPa, x2 = 0.9, V2 = 120 m/s and z2 = 1 m. The mass flow rate is dot{m} = 10 kg/s. The turbine produces Wt = 800 kW of power. Determine the heat transfer rate dot{Q} for the turbine.
(c) Explain the concept of availability and irreversibility in thermodynamics. Derive an expression for the irreversibility of a steady-flow process.
(d) A Carnot engine operates between two reservoirs at T_H = 600 K and T_L = 300 K. It receives 1000 kJ of heat from the high-temperature reservoir. Determine the net work output of the engine and the heat rejected to the low-temperature reservoir.
(e) Discuss the second law of thermodynamics and its implications. Explain the concept of entropy and its change in different processes.
