課程名稱︰單元操作三
課程性質︰必修
課程教師︰劉懷勝
開課學院：工學院
開課系所︰化工系
考試日期（年月日）︰102/3/15
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 :
Closed book :
1. (15%) The Hagen-Poiseulle law that we mentioned in class is given as below
Q = pi*R^4 * |Δp|/ 8 μl
Please state its assumptions.
And please derive the corresponding friction coefficient based on the
Hagen - Poiseulle law for the pipe flow, if tge flow rate exoression
were doubled in a very unusual case (that is, the denominator 8 ==> 4)
2. (10%) Please convert Ergun equation from the dimensionless form into
pressure drop expression. That is, convert
R'/ρu^2 = 4.17 /Re + 0.29
into |Δp|/ l = ? (1-ξ)^2 / (ξ)^3 μu/d^2 + ? (1-ξ)/ξ^3 ρu^2/d
(Please specify the notations you need.)
3. (20%) Explain the following terms breifly.
(1) specific surface area
(2) d80
(3) cylcone
(4) foam separation
(5) volume daimeter
(6) 12/24 mesh
(7) Coulter counter
(8) loading point
(9) sphericity
(10) Feret's diameter
4. (15%) Please draw illustration of a disk centrifuge and identify the flow
pattern of heavy liquid and light liquid between the disks and prove
the following sigma definition for a disk centrifuge.
** See figure 1
//
Open book
1. Explain the following questions shortly with the attached figure of pressure
drop v.s. gas rate in a packed bed. (20%)
For the cases of wet packing and dry oackingL
i. What does the slope 1.8~2.0 imply? and why?
ii. What does it imply if the slope is close to 1?
iii. Why the line of wet packing is on the left of the dry
packing line?
For various regions (lines of different slopes), please state
iv. Which phase (liquid or gas) is the dispersed phase?
v. Whether liquid hold-up is constant or not?
See figure 2.
2. A particle of density 2 g/cm^3 falling in a fluid of density of 1.6 g/cm^3
and viscosity of 1 cp was found to have a terminal velocity of 0.6 m/s.
Please estimate its size and comment on your result (e.g. Re and shape).(15%)
3. Please identify the mistake or type in the lecture note or textbook
(5% each, without limit)
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