Rr310302-hydraulic Machinery And Systems

RR

Code No: RR310302 III B.Tech. I Semester(RR) Supplementary Examinations, May 2009 HYDRAULIC MACHINERY AND SYSTEMS Time: 3 hours

(Mechanical Engineering)

Answer any FIVE questions All questions carry equal marks ?????

Max Marks: 80

1. A jet of water moving at 20 m/s impinges on a symmetrical curved vane, shaped to deflect the jet through 1200 (That is the vane angle θ and φ are equal to 300 ). If the vane is moving at 5m/s, find the angle of the jet, so that there is no shock at inlet. Also determine the absolute velocity of exit in magnitude and direction and the work done. 2. (a) Derive the expression for the efficiency of the draft tube. (b) The following data were obtained from a test on a pelton wheel; i. Head at the base of the nozzle :32m ii. Discharge of the nozzle : 0.18m3 /sec iii. Area of the Jet : 7500sq.m.m iv. Power available at the shaft: 44K.W. v. Mechanical Efficiency: 94% Calculate the power lost i. In the Nozzle ii. In the Runner. iii. In mechanical friction. 3. Discuss about the performance characteristic curves of Hydraulic turbines. 4. (a) Discuss about the effect of friction in suction and delivery pipes on Indicator diagram. (b) A double acting reciprocating pump having piston area, 0.1 m2 has a stroke 0.30m long. The pump is discharging 2.4m3 of water per minute at 45r.p.m, through a height of 10m.Find the slip of the pump and the power required to drive the pump. 5. (a) Derive the expression for work done by the Impeller of a centrifugal pump. (b) A centrifugal pump has the following characteristics. Outer diameter of the impeller: 800mm Width of Impeller vanes at outlet :100mm. Angle of Impeller vanes at outlet :400 Speed of the Impeller : 550rpm. Discharge through the impeller : 0.98m3 /sec. Effective head of the pump: 35m. A 500 K.W motor is used to drive the pump. Determine the manometric head, mechanical head and over all efficiencies of the pump. Assume that water enters the impeller vanes radially at inlet. 6. Discuss in detail about the multistage pumps used in series and parallel. 7. (a) Explain with a sketch the working of a hydraulic press. (b) A hydram uses 4m3 /minute of water under a head of 3m, and pumps 0.25m3 /minute to a tank 24m high above the ram through 150m long and 60mm diameter pipe. Take Darcy’s “ f ” for the pipe as 0.04 and calculate the efficiency of the Ram. 8. Write a short notes on the following. (a) (b) (c) (d)

Surge tanks. Indicator diagram of a reciprocating pump. Effect of vane angle on manometric efficiency. Hydraulic coupling. ?????