Indian Institute of Technology Kharagpur (IIT-K) 2008 M.Tech Chemical engineering Multiphase flow - Question Paper
From the basic momentum equation, obtain an expression of pressure gradient for air-water stratified flow through a horizontal pipe and derive the condition of choked flow under these conditions. State clearly all assumptions made. (15)
INDIAN INSTITUTE OF TECHNOLOGY DEPARTMENT OF CHEMICAL ENGINEERING
Mid Semester Examination
Multiphase Flow Subject No: CH62021 No of Students: 22 Session: 2008-2009 Full marks - 60 Answer all questions
Time: 2 hours
2. An air-water mixture flows through a circular pipe of cross-section A]. It has a nozzle of cross-section A2 at the centre. The pressure at the upstream , throat and downstream sections are pi, P2 and p3 respectively. Assuming incompressible, homogeneous flow, derive the following equations where G is the mass flux and pi and p2 are the densities of water and air respectively:
\
A _ ! .Pi
|
G2 |
A |
'a |
|
P\ |
a2 |
A2 |
G2 2/7,
A _ !
A,
P\
Pi
|
\\ |
2 |
f \ |
- | |
|
1 + X |
- 1 | |||
|
') |
Clearly state any additional assumptions made
(15)
3. (a) With the help of neat sketches distinguish between bubbly and wispy annular flow. (5)
(b) State the differences in flow patterns between gas-liquid and liquid-liquid flow patterns through a horizontal tube. (5)
State and account for the differences in flow patterns as observed during gas-liquid/vapor-liquid flow through a heated and an unheated vertical channel. (5)
(d) Mention the differences in flow patterns as observed during gas-liquid flow through a circular tube and a concentric annulus. (2)
(e) What are the differences in flow distribution one w'ould expect during flow through a 200 mm and a 2mm diameter circular tube? (3)
4. (a) On a graph of jj versus jw show lines of constant a for (a) U(/u2 = constant
(b) U12 = constant (c) j 12 = constant {d) j 12 = k a(l - a)" (8)
(b)Prove that j2Uj2 = U2Ujj 1 (2)
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| Earning: Approval pending. |
