Consider a variation of the Carnot cycle in a closed system with 10 kg of pure water operating. ranging between temperatures of 130 C and 350 ◦C. State 1 is a saturated liquid. Process 1-2 is a isothermal expansion with a supply of QH = 10 MJ. Process 2-3 is an adiabatic expansion with isentropic efficiency from 0.75 to minimum temperature. Process 3-4 is a compression isothermal, and the 4-1 process is a reversible adiabatic compression. Calculate:

A portion of a turbojet engine is shown in the figure below. Air flowing at 25 kg/s at 240 K and 80 kPa (State 1) enters an adiabatic and reversible diffuser with a velocity of 250 m/s. It leaves the diffuser with negligible velocity (State 2). As a result, you may assume the velocity of the air leaving the diffuser is small compared to the velocity of air entering the diffuser. The air is then compressed in an adiabatic compressor with an isentropic efficiency of 80%. The compressor requires 7 MW of power (work input). You may assume air is an ideal gas with constant specific heats. Use the correct specific heats in the table below in analyzing the different processes. Air Properties Cp Cy R kJ/kgK kJ/kgK kJ/kgK Diffuser (Process 1 to 2) Compressor (Process 2 to 3) 1.003 0.716 0.287 1.014 0.727 0.287 1. Calculate the pressure of the air in kPa leaving the compressor (State 3).

An engine works with two reservoirs: Ta at 400 degrees Celsius and the other Tb at 200 degrees Celsius. It goes through processes with first adiabatic compression absorbing 150 J then isothermal expansion on Ta then adiabatic expansion then isothermal compression on Tb. Output of the engine operates between the same two reservoirs, with adiabatic expansion, then  isothermal expansion at Tbthen adiabatic compression then isothermal compression at Ta. Output of engine runs refrigerator. What is the coefficient of performance of refrigerator and what is the total change in entropy in running the system?

The figure shows a reversible cycle through which 1.00 mole of a monatomic ideal gas is taken. Process bc is an adiabatic expansion, with pb = 5.80 atm and Vb = 1.00 x 10-3 m3. For the cycle, find (a) the energy added to the gas as heat, (b) the energy leaving the gas as heat, (c) the net work done by the gas, and (d) the efficiency of the cycle.