### Fluid Mechanics - Semester Exam Question

4HE Fluid Mechanics October 2000

Part A (20 x 2 = 40 Marks)

1. Differentiate between barometric pressure and absolute pressure.
2. What is meant by pressure of a liquid column?
3. Dynamic pressure is the difference between ________ and ________.
4. Define the term 'Slip velocity'.
5. Give two important industrial applications of fluidized bed.
6. Write the principle of Rotameter.
7. Give the relationship between Drag coefficient and Reynolds number in (a) Newton's range of operation
(b) Intermediate range of operation
8. Write the physical significance of Archimedes number.
9. Explain the term 'Darcy friction factor'.
10. What is meant by compressible fluids? Give two examples.
11. Write Kozeny-Carman equation for packed beds.
12. Define the term Orifice coefficient.
13. Define (a) Static suction lift (b) Static suction head.
14. Give any four important criteria involved in the selection of pumps.
15. What is meant by boundary layer thickness?
16. Differentiate between fans and blowers.
17. Write the continuity equation for compressible flow.
18. What is meant by flooding in packed towers?
19. Explain 'Cavitation' in pumps.
20. Define the term hindered settling.
21. Part B (5 x 12 = 60 Marks)

22. (a) From first principles, develop an equation for relating pressure and height, in a static fluid. Give the restrictions for the relation. (6)
(b) Discuss briefly about Non-Newtonian fluids. Give examples. (4)
(c) State Buckingham p theorem. (2)
23. Or
24. (a) How fluids are classified? Explain briefly the principles and application of an inclined manometer. (6)
(b) An open tank holds certain amount of liquid whose relative density is 1.25. The tank is fitted with manometer at a point of the wall and it shows a pressure of Pgauge = 0.35 atm. What is the height of the liquid level in the tank from the point of connection of the manometer? (6)
25. (a) What is meant by potential flow? (2)
(b) Derive Bernoulli's equation and briefly discuss the components involved in the equation. (8) (c) Write any four applications of Bernoulli equation. (2)
26. Or
27. (a) Explain the term 'skin factor' and 'form factor'. (4)
(b) How skin friction is related to pressure drop? (4)
(c) Discuss briefly about the friction factor in flow through channels of noncircular cross section. (4)
28. (a) Briefly discuss about the important flow meters used in industry. What are the advantages and disadvantages over each other? (6)
(b) Sulfuric acid of specific gravity 1.25 is flowing through a pipe of 4.5 cm i.d. A thin ripped orifice of 1.0 cm is fitted in the pipe and the differential pressure shown by the mercury manometer is 10 cm. Assuming that the leads of the manometer are filled with acid, calculate the weight of acid flowing per hour. Assume Co = 0.6 (6)
29. Or
30. Write short notes on the following: (4 x 3 = 12)
(a) Wet gas meters
(b) Hot film anemometers
(c) Magnetic flow meters
(d) Pitot tube
31. (a) Briefly discuss about the fluidization processes. What are the different types used in industry? (4)
(b) Discuss about the following: (4) (i) Porosity of static bed and porosity of fluidized bed
(ii) Minimum pressure drop and bed pressure drop in fluidized process.
(c) Differentiate between the following in a fluidized bed reactor. (4) (i) Working velocity
(ii) Actual velocity
32. Or
33. (a) What is meant by loading in a packed bed reactor? (2)
(b) Derive Ergun's equation. Extend the equation for both laminar and turbulent conditions of packed tower operation. (10)
34. (a) 60% Sulfuric acid is to be pumped at the rate of 4000 cm3/sec through a lead pipe 2.5 cm diameter and raised to a height of 25 cm. The pipe is 30 m long and includes two right angled bends. Calculate the theoretical horse power required. The specific gravity of the acid is 1.53 and its kinematic viscosity is 0.425 cm2/sec. The density of water may be taken as 1000 kg/m3.
Assume a value of roughness factor as 0.05 and R/ru2 = 0.0045 each. The velocity head loss coefficient for flow through 90o bend is 0.8. If necessary, make assumptions and mention clearly. (10)
(b) Define the term 'NPSH'. (2)
35. Or
36. (a) Compare the working principles and characteristics of centrifugal pumps with that of reciprocating pumps. (6)
(b) Discuss briefly about positive displacement pumps. Explain its function with a neat sketch. (6)

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