課程名稱︰熱力學 課程性質︰必修 課程教師︰陳瑤明 開課學院：工學院 開課系所︰機械系 考試日期（年月日）︰2012/01/12 考試時限（分鐘）：110分鐘 是否需發放獎勵金：是 （如未明確表示，則不予發放） 試題 : 1. How does the ideal Diesel cycle differ from the ideal Otto cycle? Determine the thermal efficiencies of the above mentioned cycles in terms of compression ratio, cutoff ratio and specific heat ratio. (30%) 2. Consider a steam power plant that operates on the ideal reheat cycle. The plant maintains the boiler at 7000 kPa, the reheat section at 800 kPa, and the condenser at 10 kPa. The mixture quality at the exit of both turbines is 93%. Determine the temperature at the inlet of each turbine and the cycle's efficiency. (20%) 3. Steam enters a turbine steadily at 3 MPa and 450 ℃ at a rate of 8 kg/s and exits at 0.2 MPa and 150 ℃. The steam is losing heat to the surrounding air at 100 KPa and 25 ℃ at a rate of 300 kW, and the kinetic and potential energy changes are negligible. Determine (a) the actual power output (b) the maximum power output (c) the second law efficiency (d) the exergy destroyed (e) the exergy of the steam at the inler conditions. (30%) 4. Please answer the following questions: (a) List the characteristics of a working fluid most suitable for vapor power cycles. (b) What is the differences between a refrigerator and a heat pump? Define the coefficient of performance for each of them. (c) What are the four processes that make up the Carnot cycle? (d) What is an ideal Brayton cycle? --

※ 發信站: 批踢踢實業坊(ptt.cc) ◆ From: 114.24.222.150