GTU previous question papers -BE- Sem-Vth -Fluid Power Engineering -May/June -2012

GTU previous question papers

GUJARAT TECHNOLOGICAL UNIVERSITY

BE- Vth SEMESTER–EXAMINATION – MAY/JUNE – 2012

Subject code: 151903 

Subject Name: Fluid Power Engineering

Instructions:

1. Attempt all questions.

2. Make suitable assumptions wherever necessary.

3. Figures to the right indicate full marks.

Q.1 (a) Prove that head loss due to friction is equal to one third of total head

inlet for maximum power transmission through nozzle.                          

(b) Explain the following terms : (1) Major losses (2) Minor losses and (3)

Equivalent pipe                          

Q.2 (a) A jet delivers water at the rate of 60 liters per second with velocity 30

m/s. The jet strikes tangentially on the vane moving in the direction of

the jet with the velocity of 15 m/s. The vane is so shaped that if

stationary it would deflect the jet through an angle 50°. Calculate: (1)

angle made by absolute velocity at outlet and (2) work done per sec.                          

(b) Show that in case of jet striking the flat plates mounted on wheel, the

efficiency will be maximum when the tangential velocity of wheel is half

of the jet.                          

OR

(b) A jet of water of 30 mm diameter, strikes on the hinged rectangular plate

weight 100 N at the center of the plate. The velocity of the jet is 8 m/s.

Calculate: (1) angle through which the plate will swing, and (2) force

must be applied at the lower edge of the plate in order to keep the plate

vertical.                          

Q.3 (a) Explain the following terms with reference to water turbines. Give

expression of each efficiencies.

(1) Hydraulic efficiency (2) Mechanical efficiency and

(3) Overall efficiency                          

(b) The following data is related to Pelton wheel turbine

(1) Heat at the base of the nozzle=80 m

(2) Diameter of the jet = 100 mm

(3) Discharge of the nozzle=0.30m3/s

(4) Power at the shaft=206 kw and

(5) Power absorbed in mechanical resistance= 4.5 kw

Determine: (1) power lost in nozzle and (2) power lost due to hydraulic

resistance in the runner.                          

OR

Q.3 (a) Why governing of water turbine is required? Explain governing of any

one hydraulic turbine with neat sketch.                          

(b) Francis turbine designed to develop 160 kw working under a head 10 m

and running at 200 rpm. The hydraulic losses in turbine are 15% of

available energy. The overall efficiency of turbine is 80%. Assume flow

ratio=0.94 and speed ratio=0.25. Calculate: (1) guide blade angle and

runner vane angle at inlet and (2) diameter and width at inlet.                          

Q.4 (a) Enlist the various types of impeller used in centrifugal pump and explain

any one from it with a neat sketch .                          

(b) Find the power required to drive a centrifugal pump which delivers 0.04

m3/sec of water to a height of 20m through a 15 cm diameter pipe and

100 m long. The overall efficiency of the pump is 70% and co efficient

of friction f=0.015 used in Darcy’s equation.                          

OR

Q.4 (a) Give classification of Reciprocating pump. Draw neat sketch of single

acting reciprocating pump

                          

(b) Write a short note on Submersible pump.                            

Q.5 (a) Derive an expression for the optimum value of the intercooler pressure

in a two stage reciprocating air compressor for perfect inter cooling condition.                          

(b) A centrifugal air compressor has a pressure ratio of 4:1 with an

isentropic efficiency 88% when running at 14000 rpm and including air

at 25° C. Curved vanes at inlet give the air a pre-whirl of 18° to axial

direction at all radii and the mean diameter of eye is 245 mm. The

absolute air velocity at inlet is 120 m/s. Impeller tip diameter is 580 mm.

Calculate slip factor.                          

OR

Q.5 (a) With a suitable sketch explain the working principle of an axial flow

compressor. Draw the stage velocity triangles.                           

(b) Explain working of Differential hydraulic accumulator with neat sketch.                            

 

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