# GTU previous question papers -BE- Sem-Vth -Fluid Power Engineering -June -2011

GTU previous question papers

GUJARAT TECHNOLOGICAL UNIVERSITY

B. E. Sem. – V – Examination – June- 2011

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) With usual notations derive Darcy-Weisbach expression for

calculating head loss due to friction in a pipe.

(b) The diameter of a horizontal pipe which is 300mm is suddenly

enlarged to 600mm. The rate of flow of water through this pipe is

0.4 m3/sec. If the intensity of pressure in smaller pipe is 125 KN/m2,

determine loss of head due to sudden enlargement, intensity of

pressure in large pipe, power loss due to enlargement.

Q.2 (a) With neat sketch explain construction and working of hydraulic

crane.

(b) Prove that for a curved radial vane the efficiency is given by

η= 2(Vw1u1+- Vw2u2)

V2

1

OR

(b) A jet of water moving with a velocity of 27m/s impinges

tangentially to a single curved blade which is moving in the

direction of jet with a speed of 12m/s. Jet is deflected through 45°. If

the friction reduces the relative velocity by 20% calculate the angle

through which the jet will leave the blade, work done /kg of water and efficiency.

Q.3 (a) Explain how hydraulic turbines are classified.

(b) A Pelton turbine is to be designed for following specifications:

efficiency=86%, jet diameter not to exceed one sixth of wheel

diameter, Determine the wheel diameter, number of jets required,

diameter of jet. assume Cv=0.985, v=0.45(2gH)0.5

OR

Q.3 (a) State function of draft tube and explain with neat sketch different

types of draft tubes.

(b) A turbine is to operate under a head of 25 m at 200rpm. The

discharge is 9m3/sec. If the efficiency is 90% determine, specific

speed of machine, power generated, type of turbine and performance

Q.4 (a) Explain following terms: Net positive suction head, Priming,

Cavitation in pump.

(b) A centrifugal pump raises the head of water through 4m and delivers

1.5m3/sec. The speed of the impeller is 180rpm. The impeller

diameter at the outlet is 1.3m and area at the periphery is 0.3m2. The

ratio of the outlet at the inlet diameter is 2m and vane angle at the

outlet is 30° .Determine the hydraulic efficiency, power required and

minimum starting speed.

OR

Q. 4 (a) With neat sketch explain construction and working of submersible pump.

(b) A triple cylinder reciprocating pump raises the water level by 100m

and discharge is 100l/s. The diameter of piston is 250mm and stroke

is 600mm.The velocity of water in the delivery pipe is 1.4m/s. The

friction losses amount to 2m in the suction pipe and 18m in delivery

pipe. Taking efficiency of pump as 90% and slip 2%, calculate

speed and power input of the pump.

Q.5 (a) Derive an expression for indicated work of reciprocating air

compressor considering its clearance.

(b) In a three stage compressor, air is compressed from 98KPa to

20 KPa .Calculate for 1m3 of air per second,

(1) Work under ideal condition for n=1.3

(2) Isothermal work.

(3) Saving in work due to multi-staging.

(4) Isothermal efficiency.

OR

Q.5 (a) Describe principle construction and working of centrifugal compressor.

(b) A centrifugal compressor running at 1440rpm, handles air at

101KPa and 20 °C and compress it to a pressure of 6 bar

isentropically. The inner and outer diameters of the impeller are

14cm and 25cm, resply, The width of the blade at the inlet is 2.5cm.

The blade angles are 16° and 40° at entry and exit. Calculate massflow

rate of the air degree of reaction , power input and width of the, blades at outlet.