Question

(30 points) A magic substance (identical phase change temperatures to water, but having difference thermodynamic properties) contained in a piston-cylinder assembly undergoes two processes in series from an initial state where the pressure is 10 bar and the temperature is 400 C. In Process 1-2, the substance is cooled as it is compressed at a constant pressure of 10 bar to the saturated vapor state. In Process 2-3, the substance is cooled further at constant volume to 150 °C. a. Sketch both processes on T-v and p- v diagrams. i. Additional information: At 10 bar, Tsat-180 °C. b. For the overall process, determine the work in kJ/kg and explain the direction of work. i. Additional information At 10 bar and 400 °C, specific volume and internal energy: U = 0.3 m3/kg, u = 3000 kJ/kg. The specific volume of saturated vapor state is 0.2 m/kg c. For the overall process, determine the heat transfer in kJ/kg and explain the direction of heat transfer i. Additional information At 150 °C, vr 1.0 x 10-3, vg - 0.4 m'/kg, but assume that vf is much smaller than va, so it can be assumed to be zero in steam quality calculation, At 150 °C, u 600 kJ/kg and ug 2600 kJ/kg. Magic substancee

Answer 1