Test 2
Test 2 covers the course objectives of applying the properties of Rankine cycles with superheating, reheating, and regeneration to steam plant; defining thermal efficiency, second law efficiency, and energy availability; and to develop a clear understanding of the basic operation of combined gas turbines vapor cycles, co-generation and binary vapor cycles. In comparison to the provided solution set, for problem 1, I incorrectly filled out the t-s diagram. In addition, I had multiple incorrect values within my states that contributed to incorrect solutions. In solving for the mass fraction “y”, I used the incorrect formula referencing enthalpy 2 instead of 3 as well as referencing enthalpy 4 instead of 3. This occurred because of improper application of the first law to mixing chamber. That cascaded more wrong information into the values for the other mass fractions. The Q value is a very high number that when computed I was skeptical of but simply did not have the time to correct, as well as the thermal efficiency being 144% is a clear error that while I acknowledge it is an impossible value. For problem 1 I believe that issues came up because of my application and use of the laws of thermodynamics. In comparison to the solution set for problem 2, once again, my drawing of the t-s diagram was incorrect and I had incorrect final answers. However, for the calculations done I received full credit for them which tells me that I was headed in the correct direction, but with incorrect variable values.
I believe that the grade I received on this exam was fair. It was a difficult test with many states that required much time and effort to complete. During the test I had many issues solving values at the states. During the exam I practiced patience and did my best to answer the questions as I could. In this process I learned about fractions of mass. Fraction of mass is used to calculate the vapor in steam which is helpful in developing steam powered plants. As of right now I don’t know where I could apply that specifically. Nor have I needed to outside of this course, however, it is undoubtedly an important Process to know when there are multiple connections to a single turbine. This test I believe I did the best on question 2 as I was able to work much faster on that one and I feel that my work was more clear and concise. This test was difficult for me as I spent about 40 hours nonstop working on it. The greater portion of a full day was use just to determine the states for question one. Each answer that I got I was unsatisfied with and needed to restart until I ended up with what I submitted. Following that, around 10 hours was used to complete the calculations for question one and the remainder of the time was used for question 2. I don’t know what I could have done differently other than to get the correct answers earlier when calculating the states.
