课程名称︰热力学 课程性质︰系定必修 课程教师︰苏金佳 开课学院：工学院 开课系所︰机械系 考试日期（年月日）︰081113 考试时限（分钟）：├←50分→┼← 60分 →┤ │openbook│close book│ 第一部分:███████████ 第二部份: ██████ 是否需发放奖励金：是 试题 : 第一部份 1. A 0.5m^3 adiabatic rigid container is divided into two equal volumes by a thin membrane. Initially, one of these chambers is filled with air at 500kPa and 50 degrees Centigrade while the other chamber is evacuated. Determine the internal energy change of the air when the membrane is ruptured and the final air pressure in the container. (10%) 2. An oil pump is drawing 52kW of electric power while pumping oil with ρ=830kg/m^3 at a rate of 0.15m^3/s. The inlet and outlet diameters of thep pipe are 10cm and 15cm, respectively. If the pressure rise of oil in the pump is measured to be 380kPa and the motor efficiency is 89%, determine the mechanical efficiency of the pump. (15%) 3. A steam turbine operates with 1.8MPa and 360 degrees Celsius steam at its inlet and saturated vapor at 40 degrees Celsius at its exit. The mass flow rate of the steam is 15kg/s, and the turbine produves 8400kW of power. Determine the rate at which heat is lost through the casting of this turbine. 第二部份 4. What is wrong with the following differentiation of work in thermodynamic analysis? (10%) dW = d(PV) = (dP)V + P(dV) 5. Explain the difference between thermal and mechanical equilibriums of a system. (5%) 6. Explain the reason that, instead of internal energy, enthalpy is often used in control-volume analysis. (10%) 7. Explain the following terms: (a) compressibilith factor, (b) latent heat, (c) heating value of fuels, (d) triple point and (e) critical point. (5%each, 25%total) 8. Schematically draw a P-v diagram of a pure substance. On the diagram show two isothermal lines of different temperatures and indicate the following regionsL saturated liquid, saturated vapor, wet region and compressed liquid. (10%) -- 嘘 :你po这什麽豪洨文 我抓! → dn890221:楼上啊 什麽"抓"啊? → :有没有玩过吹牛啊楼上? --

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