# 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:

shaft power=11770KW, Head=380m, speed=750rpm, overall

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

under head of 20 m.** **

**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.

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