Problem 2: Air expands in a turbine from T1 = 1000 K and P1 = 1 MPa to a final pressure equal to P2 = 300 kPa in a turbine with isentropic efficiency equal to 85%. Please answer the following:
a. Represent the process in a T-s diagram. Include the isobars with their value.
b. Compute the work per unit mass of air flowing using the method of constant specific heats. Explain your procedure, in particular the temperature used to extract the value for the specific heat.
c. Compute the work per unit mass of air using the method of variable specific heats.
d. Now you want to study the effect of the exit pressure, P2, on the work produced (kJ/kg) and the air exit temperature (K) for the same turbine with isentropic efficiency equal to 85% when the exit pressure P2 decreases in discrete intervals of 50 kPa each in the interval P2 = [300, 100] kPa. For your solution you are asked to generate values that correspond to pressure decrements of 50 kPa and show them in a plot. You may perform the computation for the plot values using your calculator and values from tables, or using MATLAB or any other numerical tool to generate the plot. In your plot include the name of the variable on the axes. Note that if you intend to code it may be best that you streamline your computation procedure such that it can be repeated. Both curves, work per unit mass and temperature, should appear in the same graph. Note: you can use your solution in part (c) to validate your plot when P2 = 300 kPa.