課程名稱︰分離程序 課程性質︰化工系大三必修 課程教師︰劉懷勝教授 開課學院：工學院 開課系所︰化學工程學系 考試日期（年月日）︰2020.04.07 考試時限（分鐘）：100分鐘 試題 : Closed Book: 1. (20%) Please derive from the Hagen-Poiseulle law Q=(pi*(R^4)*deltaP)/(8*u*l) (u為黏度) into Carman-Kozney equation as uc=[(1/180)*(e^3/(1-e)^2)]... (講義上的公式，麻煩自己去翻一下，這裡不好打QQ). Show your steps and specify all the notation you need. 2. (10%) The size distribution of a dust as measured by a microscope is as follows. Convert these data to obtain the distribution on a mass basis, and calculate the specific surface, assuming shpereical particals of the density of 2650 kg/m^3 Size Range(um) Number of particals in range(-) 0-2 2000 2-4 600 4-8 140 8-12 40 12-16 15 16-20 5 20-24 2 3. (10%) Please calculate the shape factor and specific surface area(based on bed volume) of Rasching rings(0.25 inch diameter, 0.03 inch wall thickness, 62% free space, 1 inch tall). 4. (10%) Briefly explain the difference of sludge line settling and selective settling. Open Book: 1. (25%) When calculating terminal velocity of a sphere with known diameter, it is shown in our lecture note(3) that we could avoid trial and error if using Galileo Number(Ga) to transform Stokes' law Cd=R/rho*u^2=12/Re into Ga=18*Re when Ga<3.6 and so on. Please do the similar derivation for the case of obtaining particle diameter with a known terminal velocity. You need a "new" dimensionless number so that we do not need partical diameter during calculation. Also derive proper eqations for Stokes' region as well as Newton's region. 2. (25%) A column 0.6 diameter and 4 m high is, packed with 25mm Rasching (656 m^2/m^3, void fraction 0.71) and used in a gas absorption process carried out at 101.3kN/m^2 and 293K. If the liquid and gas approximate to those of water and air respectively and their flow rates are 2.5 and 0.6 kg/m^2*s. What is the pressure drop across the column? By how much may the liquid flow rate be increased before the column floods? (第一小題需要有數字，第二小題說出用哪張圖比較以及概略情況即可) --

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