BBA Iind SEMESTER EXAMINATION 2008-09 s14

B.Tech VII (Seventh) Semester Examination 2015-16

Course Code: EME707 Paper ID: 0967128

Hydraulic Machines

Time: 3 Hours Max. Marks: 70

Max Marks: 75 Note: Attempt six questions in all. Q. No. 1 is compulsory.

1. Answer any five of the following (limit your answer to 50 words). (4x5=20) a) Differentiate between pipe flow and open channel flow.. b) Explain the term hydraulic pump and hydraulic accumulator. c) Define the term Reynolds’s number and Froude’s number. d) What is priming of a centrifugal pump? Why is it necessary? e) What is a draft tube? Why is it used in a reaction turbine? f) What is reciprocating pump? Describe the principle and working of a reciprocating pump. g) Find the number of pumps required to take water from a deep well under a total head of 89 m. All the pumps are identical and are running at 800 r.p.m. The specific speed of each pump is given by 25 while the rated capacity of each pump is 0.16 m3/S. h) Differentiate between the impulse and reaction turbine.

2. A pelton wheel is to be designed for the following specifications: Shaft power = 11772 kW, Head = 380m, Speed = 750 rpm Overall efficiency = 86%, Jet diameter to wheel diameter ratio is not to exceed one sixth (1/6). Find- (10) a) The wheel diameter b) The number of jets required c) Diameter of the jet Given Kv 1= 0.985 and Kul = 0.45.

3. A pelton wheel has a mean bucket speed of 10 meters per second with a jet of water flowing at the rate of 700 liters/s under a head of 30m. The buckets deflect the jet through an angle of 1600 calculate the power given by water to the runner and the hydraulic efficiency of the turbine. Assume coefficient of velocity as 0.98. (10)

4. Explain the following terms: (2.5x4=10) a) Negative slip b) Concept of Slip c) Use of Air Vessel d) Hydraulic press

5. A Francis turbine works at 450 r.p.m under a head of 120 m. If diameter at inlet is 1.20 m and flow area at inlet is 0.4m2. The angle mad by Absolute and Relative velocity with Tangent of Runner at inlet is 20⁰ and 60⁰. Determine flow rate, Runner power developed and Hydraulic Efficiency. Assuming whirl velocity at outlet is zero. (10)

6. Explain the Construction, working principle and applications of single and double acting reciprocating pumps. (10)

7. Explain the Construction and working of air lift pump and jet pump. (10)

8. Prove that work done per second per unit weight of water in a reaction turbine is given as:

1 g (Vw1U1 Vw2U 2 )

Where vW1 and vW2 = velocities of whirl at inlet and outlet. (10)