4HE Fluid Mechanics - October 1998

Part A - (20 X 2 = 40 marks)

1. Differentiate between Newtonian and Non-Newtonian fluids.
2. Write the unit for surface tension coefficient.
3. What are the two important characteristics of potential flow?
4. Define 'mass velocity' of fluid through a channel.
5. What is Mach number? Define the Mach number for an ideal gas.
6. Define 'Boundary Layer'.
7. Write Ergun's equation for pressure drop through a packed bed.
8. Classify positive displacement pumps.
9. Write an expression for head loss due to sudden expansion of the fluid.
10. Write the physical significance of Froude's number.
11. Write few industrial applications of fluidized beds.
12. Inclined manometer is used for ____________.
13. Define 'Manometric efficiency' in centrifugal pump.
14. Write the principle of Pitot tube.
15. Why is rotameter called an area meter?
16. What is 'What Hammer'?
17. What is Priming?
18. What is the function of volute in a centrifugal pump?
19. Write two differences between compressors and blowers.
20. Define 'Form drag' and 'Skin drag'.
21. Part B - (5 X 12 = 60 marks)

22. (a) With the help of shear stress-shear rate diagram, explain the classification of non-Newtonian fluids. Discuss their important characteristics. (8)
23. (b)A simple U-tube manometer is installed across an orifice meter. The manometer is filled with mercury (sp.gr = 13.6) and the liquid above the mercury is carbon tetra chloride (sp.gr = 1.6). The manometer reads 300 mm. What is the pressure difference over the manometer in Newtons per square meter? (4)

Or

24. (a) Define Similitude. Explain the different types of similarities in fluid flow processes. (4)
25. (b) Pressure drop of a homogeneous fluid in a straight smooth pipe (DP) is a function of the pipe geometry (diameter d, and length l), the physical properties of the fluid (densityr and viscosity m) as well as its velocity v.

DP = f (d, l, r, m, v)

Using dimensional analysis, find out the relationship between dimensionless groups, defining the above fluid flow process. (8)

26. (a) Assuming one dimensional fluid flow, write the continuity, momentum and mechanical energy equations for an incompressible fluid. (6)
27. (b) Discuss the velocity profiles for laminar and turbulent fluid flow through a pipe. What is the relationship between skin friction and wall shear in a pipe? (6)

Or

28. (a) Discuss the various zones for development of turbulent boundary layer on a flat plate. (4)
29. (b) Brine is to be pumped through a 25 m of smooth copper tube having an inside diameter of 2.5 cm. Flow rate of brine is 100 litre/min. Calculate the following:
(i)Pressure drop from friction in kN/m2
(ii)Power required to overcome friction.

Data:
Specific gravity of brine = 1.15
Viscosity of brine = 2.5 cp
Friction factor f = 0.0015 + 0.125Re-0.33  (8)

30. (a) Explain the principle, construction and working of an orifice meter with the help of a neat sketch. (6)
31. (b) Discuss the principle and applications of Doppler effect in flow measurement. (6)

Or

32. (a) Compare between an orifice meter and venturi meter. (4)
33. (b) An oil of specific gravity 0.8 is flowing through a venturi meter having inlet diameter 20 cm and throat diameter 10 cm. The mercury differential manometer shows a reading of 25 cm. Calculate the discharge of oil through the horizontal venturi meter. Take Cd = 0.98 (8)

34. (a) With the help of a neat sketch, explain the flow of fluid through granular solids. (6)
35. (b) Derive Carman-Kozney equation for pressure drop through a packed bed. (6)

Or

36. (a) Explain the different types of fluidization and state their conditions. State commercial applications of fluidized bed. (6)
37. (b) Differentiate between Loading and Flooding. How will you estimate the flooding velocity in a packed tower? (6)

38. (a) Classify pumps. With the help of a neat sketch, explain the operation of a centrifugal pump. (6)
39. (b) State the principle and applications of air lift and diaphragm pumps. (6)

Or

40. (a) Explain the principle of operation for fans, blowers and compressors. (6)
41. (b) A centrifugal fan is used to take flue gas at rest and at a pressure of 700 mm Hg and a temperature of 90oC and discharges it at a pressure of 765 mm Hg and a velocity of 45 m/s. Calculate the power required to move 18000 m3/hr of gas. Efficiency of the fan is 65%. Molecular weight of the gas = 32. (6)