ME 203 Thermodynamics-1 Due Date: 28.11.2013 Homework 2

Problems

1. Air undergoes a reversible thermodynamic cycle 1-2-3-1 as shown in figure on the right. Process 1-2 is isothermal expansion, 2-3 is constant pressure, and process 3-1 is constant volume. Determine the work and the heat interactions and the change of internal energy for each process and for the entire cycle.

2. Referring to figure, water contained in a piston cylinder assembly, initially at 1.5 bar and a quality of 20%, is heated at constant pressure until the piston hits the stops. Heating then continues until the water is saturated vapor. Show the processes of the water in series on a sketch of the Tv diagram. For the overall process of the water, evaluate the specific work and heat transfer, each in kJ/kg. Kinetic and potential effects are negligible.

3. An uninsulated frictionless piston is initially constrained in a rigid insulated cylinder. As shown in figure below, air (assumed to be ideal gas) is trapped on both sides of the piston. The piston is freed, and equilibrium is reestablished.

a. What is the final pressure? b. If the system boundary is imagined to pass through the piston, will heat

be transferred? Explain.