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Reg. No. : .................................... Name : .........................................
Third Semester B.Tech. Degree Examination, November 2009 (2003 Scheme) Branch : Electrical 03-303 : HYDRAULIC MACHINES AND HEAT ENGINES (E) Time : 3 Hours
Max. Marks : 100
Instruction: Answer all questions from Part – A and any one question from each of the Module of Part – B. PART – A 1. Explain the phenomenon of capillarity. Derive an expression for capillary rise of a liquid. 2. Calculate the pressure inside a liquid droplet of water of 0.4 cm in diameter. Assume surface tension of water as 0.073 N/m and the atmospheric pressure as 1 bar. 3. Obtain Bernoulli’s equation from Euler’s equation. 4. What is Reynold’s Number ? Explain its significance. 5. Describe the function of surge tanks in hydro electric projects. 6. The well in a house has a water level 15 m below the ground level. Can a centrifugal pump be installed at the ground level to pump water ? Justify your answer. 7. Explain the working of a jet pump. 8. What is a draft tube ? Explain its functions. 9. Explain the terms : a) Indicated power b) Brake power c) Mean effective pressure. 10. Differentiate between the terms impulse and reaction as applied to a steam turbine. (4×10=40 Marks) P.T.O.
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PART – B Module – 1 11. a) State and prove Pascal’s law. b) A piston of 6.0 cm diameter rotates concentrically inside a cylinder 7 cm diameter. Both the piston and the cylinder are 8 cm long. Find the tangential velocity of the piston if the space between the cylinder and the piston is filled with oil of viscosity 2.35 poise and the torque of 1.4 N-m is applied. OR 12. a) Derive an expression for the theoretical discharge of a venturimeter. b) A pipe of 0.6 m diameter is 1.5 km long. In order to augment the discharge, another line of the same diameter is introduced parallel to the first in the second half of the length. Neglecting the minor losses, find the increase in discharge if friction factor is 0.04. The head at inlet is 30 m. Module – 2 13. a) Sketch a Francis turbine and explain its working. b) Describe with a sketch the working of a system to regulate the speed of a Pelton turbine. OR 14. a) Explain the indicator diagram of a reciprocating pump without air vessel. b) A reciprocating pump has piston diameter 30 cm and stroke 45 cm. The suction pipe is 12.5 cm in diameter and 8 m long. The centre line of the pump is 4 m above the level of water in the pump. Calculate the maximum speed of the pump if the atmospheric pressure is 10.3 m of water and vapour pressure is 2.5 m of water. At this speed, calculate the discharge and pressure head at the middle and end of the suction stroke. Take f = 0.02.
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Module – 3 15. a) Describe the procedure used in preparing the heat balance sheet of a Internal Combustion Engine. b) What is the need of compounding ? With neat sketches describe pressure compounding and velocity compounding. OR 16. a) Derive an expression for the optimum pressure ratio for obtaining maximum thermal efficiency for a gas turbine cycle. b) Describe the various methods used to increase the efficiency of a gas turbine (20×3=60 Marks)
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