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)