7/30/2019 r5222203-Prime Movers & Mechanical Components

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Code :R5222203 R5

II B.Tech II Semester (R05) Supplementary Examinations, December 2010PRIME MOVERS & MECHANICAL COMPONENTS

(Instrumentation & Control Engineering)Time: 3 hours Max Marks: 80

Answer any FIVE questionsAll questions carry equal marks

1. (a) Describe any eight points of distinction between impulse and reaction turbines.

(b) A Francis turbine is required to develop a power of 330KW under a head of 30m while operatingat 350 rpm if overall efficiency =80% hydraulic efficiency =88% speed ratio =.075, flow ratio=0.25and ratio of outer to inner dia =2 calculate the blade angles at inlet and outlet and the dimensionsof the runner.

2. (a) List out all the losses that occur in a centrifugal pump and define the four pump efficiencies.

(b) A single-acting reciprocating pump has a plunger of diameter = 20 cm, stroke = 32 cm, suctionpipe diameter = 10 cm,, length = 8 m, static suction lift =3.5 m, f =0.032. assuming Patm=10.3m of water and Pavg=2.6 m of water (abs), calculate the maximum rpm at which the pump can

be operated without causing separation when there is no air vessel and a large air vessel is fittedto the suction pipe at a distance of 1 m from the pump.

3. (a) Explain the following boiler terms:

i. Boiler shellii. Combustion Chamber

iii. Grateiv. Furnacev. Heating surface

vi. Mountings and Accessories

(b) What are the factors should be considered while selecting a boiler?

4. (a) Explain why the blow-off cock is operated periodically when the boiler is working?

(b) What is the function of following boilers mountings.i. Water level indicator.

ii. Pressure gauge.iii. Safety valve.iv. Fusible plug.v. Blow-off cock.

vi. Feed check valve.

5. (a) Why the Carnot cycle cannot be considered as the theoretical cycle for steam power plants eventhough its efficiency is maximum?

(b) A Carnot cycle steam power plant operates between the temperatures of 4000C and 1000C.Calculate Carnot cycle efficiency.

(c) Why pure reaction turbine is not used in practice?

6. (a) Explain clearly the differences between open cycle gas turbine and closed cycle gas turbine.

(b) Draw the temperature-entropy (T-S) diagram of a ideal Joule cycle for a gas turbine plant andexplain each process briefly.

7. (a) Draw a neat sketch to explain the construction and operation of a hydraulic press.

(b) A hydraulic press has a ram of 10 cm diameter and a plunger of 1.25 cm. What force will berequired on the plunger to raise a load of 20 kN on the ram? If the plunger has a stroke of 20cm, how many strokes will be required to lift the load by 60 cm? Also calculate the volume ofadditional liquid required. Further if the time taken to lift the load is 10 minutes, what shouldbe the power of the motor required to drive the plunger? Neglect frictional effects.

8. What do you mean by constrained motion? What are the different types of constrained motion?Explain each type with examples and neat sketches.

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