課程名稱︰熱力學
課程性質︰必修
課程教師︰許文翰
開課學院：工學院
開課系所︰工程科學與海洋工程學系
考試日期（年月日）︰2008/6/19
考試時限（分鐘）：120
是否需發放獎勵金：是
（如未明確表示，則不予發放）
試題 :
Thermodynamics Final 6/19/2008
1.An ideal-gas turbine operates with a pressure ratio of 8:1 and temperature
limits of 20'C(度C) and 1000'C. The energy input in high temperature that
exchanger is 200kW. Determine (a) the air flowrate; (b)the percentage of
turbine work used by the compressor.(20pt)
2.An engine operates on the air-standard Otto cycle. The pressure and
temperature at the beginning of isentropic compression are 120kPa and 35'C
respecticvely. The peak pressure and temperature are 4.8MPa and 2500'C.
Determine (a) the net cycle workin kJ/Kg; (b)the cycle efficiency. (20pt)
3.An air-standard Diesel cycle receives 28.5kJ/cycle of heat while operating
at 300rev/min. At the beginning of compression, p1=100kPa, T1=305K,
V1=0.0425m^3. At the beginning of heat addition, the pressure is 3450kPa.
Determine (a) the work; (b) the power, (c) the mean effective pressure.
(20pt)
4.A reciprocating compressor has a 5% clearance with a bore and stroke of 25cm
and 30cm. The compressor operates at 500rev/min. The air enters the cylinder
at 27'C and 95kPa and discharges at 2000kPa. If n=1.3 for compression and
expansion processes. Determine (a)the volumnetric efficiency; (b) the power
required; (c)the mass of air discharged in kg/s. (20pt)
5.A gas turbine expands 50kg/s of Helium polytropically, pV^1.8=C, from 1100K
and 500kPa to 350K. Determine (a) the entropy change; (b)the final pressure;
(c)the heat loss. (20pt)
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