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Reg. No. : .................................... Name : .........................................
Third Semester B.Tech. Degree Examination, June 2009 Branch : Chemical Engineering 03-304 : FLUID FLOW OPERATIONS – I (H) Time : 3 Hours
Max. Marks : 100 PART – A
Answer all questions from Part – A. All questions carry four marks. 1. a) Briefly discuss about fabrication of orifice meters. What are the factors to be considered when orifice plates are fabricated ? b) Discuss briefly on laser dropler anemometry. c) Explain the term cavitation. How do you avoid cavitation ? d) A u-tube manometer reads a level difference of 8 cm of water when used in a pipe in which air is flowing. Calculate the pressure difference. e) Define the terms buoyancy and centre of buoyancy. f) Briefly explain the principle of gravity decanters. g) What do you understand by the terms real fluids and ideal fluids ? Give examples for each category. h) Give Bernoulli’s equation. Explain the corrections applied to it. Why do one apply these corrections ? i) Using Bernoulli’s equation derive a relationship for the velocity through an opening in a tank in which a liquid is stored up to a height h. j) Name four different pipe fittings that are generally used. Comment on their utility. How do one select these fittings ?
P.T.O.
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PART – B Answer any one full questions from each Module in Part – B. One full question carry twenty marks. Module – 1 2. a) Derive a relationship for the pressure difference between the inner and outer peripheries of the liquid in motion in a centrifugal bowl.
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b) A rectangular pantoon is 5m long, 3 m wide and 1.2m high. The depth of immersion of the pantoon is 0.80m in sea water. If the centre of gravity 0.6m above the bottom of the pantoon, determine the meta-centric height. The density of sea water can be taken as 1025 kg/m3. 10 3. a) A vertical continuous decanter is to separate 9.93 m3/h of a liquid petroleum fraction from an equal volume of wash acid. The density of the petroleum fraction is 865 kg/m3, that of the acid is 1153 kg/m3. The required settling time is 20 min. Compute the size of the vessel and the height of the acid overflow above the floor of the vessel. 10 b) A jet of water from a 25 mm diameter nozzle is directed vertically upwards. Assuming that the jet remains circular and neglecting any loss of energy, what will be the diameter at a point 4.5m above the nozzle, if the velocity with which the jet leaves the nozzle is 12 m/s. 10 Module – 2 4. Starting from first principles derive Bernoulli equation without friction. 5. a) Briefly explain the practical use of velocity heads in the design of piping systems. b) Discuss about boundary layer separation in diverging channels.
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c) Derive an expression for velocity distribution for flow of viscous fluids through circular pipes. 10
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Module – 3 6. a) Derive a relationship for calculating the velocity of a fluid measured using a pitot 10
tube. b) A pitot-static tube placed in the centre of a 30 cm pipe line has one orifice pointing upstream and the other perpendicular to it. The mean velocity in the pipe is 0.8 fraction of the velocity at the centre. Find the discharge through the pipe if the pressure difference between the two orifices is 6 cm of water. Take the coefficient of the pitot tube as 0.98.
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7. The internal and external diameters of the impeller of a centrifugal pump are 20 cm and 40 cm respectively. The pump is running at 1200 rpm. The vane angles of the impeller at inlet and outlet are 20° and 30° respectively. The water enters the impeller radially and velocity of flow is constant. Determine the work done 20
by the impeller per kg of water. ———————