课程名称︰单元操作 课程性质︰授课无实验 课程教师︰吕理平 开课学院：化工系 开课系所︰化工系 考试日期（年月日）︰99/1/14 考试时限（分钟）：open 50 close 90min 是否需发放奖励金：是 （如未明确表示，则不予发放） 试题 : Transport Phenomena and Unit Operations(II) Final Examination(closed book section) 1.(20%)Explain the following terms or questions briefly: (a)Fick's first law and Fick's second law of diffusion (b)Higbie's and Danckwert's penetration model (c)Schmidt number and Prandtl number (d)Differences between heat transfer by the energy diffusion and heat transfer by the radiation 2.(15%) An 8 cm internal diameter, 10 cm high mug is left in a dry air at 20"C,1 atm with its top open. If the water level in the mug is 8 cm high from the bottom and is maintained at 20"C , determine how long(in hours)it will take for the water evaporation and the water level becoming 4 cm high from the bottom. Data: at 20"C vapor pressure of water = 2.339 kPa mass diffusivity of water vapor in air = 2.71*10^-5 m2/s 3.(15%) For the very long grooves(very long in direction perpendicular to the paper) shown in the following figures, please find view factor F12 in case(a),F(1+3)2 in case(b)and F21 in case (c). --

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