Winter 2014 Fluid Mechanics and Hydraulic Machines Question Paper

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GUJARAT TECHNOLOGICAL UNIVERSITY
Diploma Engineering - SEMESTER–III • EXAMINATION – WINTER • 2014
Subject Code: 3331903 Date: 01-12-2014
Subject Name: Fluid Mechanics and Hydraulic Machines
Time: 10:30 am - 01:00 pm Total Marks: 70

Instructions:
1. Attempt all questions.
2. Make suitable assumptions wherever necessary.
3. Figures to the right indicate full marks.
4. English version is considered to be Authentic.

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Q.1 Answer any seven out of ten. 14

1. Give the S.I unit of following fluid properties.
(i) Dynamic viscosity (ii) Kinematic viscosity (iii) Bulk modulus (iv) Specific weight.

2. Differentiate between ideal fluid and real fluid.

3. A liquid has density 1600 kg/m3. Calculate its specific gravity.

4. Explain Newton’s law of viscosity.

5. Find the equation between gauge pressure and absolute pressure.

6. Determine the pressure in N/m2 at a depth of 5m below the surface of an oil specific
 gravity of 0.75.

7. Classify pressure measuring devices.

8. Draw a neat sketch of a Burden tube Pressure Gauge.

9. Fill in the blanks. (i)1 bar = ________ Pa. (ii) 760 mm of Hg.= ______ m of water.

10. State Pascal’s Law.

Q.2 (a) Differentiate between following :( Any two)
(i)Steady flow and Unsteady flow (ii) Rotational flow and irrotational flow
(iii)Laminar flow and turbulent flow. 03

OR

(a) Define following terms. (any three)
(i)Stream line (ii) Streak line (iii) Path line (iv) Stream tube (v) Flow net 03
(b) State and derive continuity equation. 03

OR

(b) The pipe discharging 70 liter/second has 30cm diameter at inlet changing to 10 cm
diameter at outlet. Compute flow velocity at both ends. 03

(c) Derive Bernoulli’s equation from Euler’s equation. 04

OR

(c) Water flow with 150lt/sec in a pipe. The diameter of pipe is 250mm and pressure is 450KPa.
 If the centre line of pipe is at 10m from the base, find the total energy. 04

(d) Explain the term “Impact of jet”. Derive the equation of force due to impact
of jet on stationary flat vertical plate. 04

OR

(d) A 5cm diameter of jet moving with a velocity of 30m/s, is strikes a moving flat
plate normal to the jet. Plate is moving with a velocity of 8 m/s. Calculate work
done per sec and efficiency. 04

Q.3 (a) State the equation for measuring flow through following devices.(any three)
(i)Circular orifice (ii) Rectangular Notch (iii) Venturimeter (iv) Pitot tube 03

OR

(a) Explain following hydraulic co-efficient.
(i)Co-efficient of contraction (ii) Co-efficient of Discharge (iii) Co-efficient of velocity 03

(b) A horizontal venturimeter is use for measuring discharge of water, whose inlet and throat diameters are 75 mm and 25 mm respectively. The reading of differential manometer connected between inlet and throat is 41.2 cm of mercury. If the co-efficient of venturimeter is 0.97, find the discharge. 03

OR

(b) Discharge through rectangular notch is 24m3/min. When head of water is one third of length of notch, calculate length of notch. Take Cd = 0.62. 03

(c) Explain water hammer and arrangement to overcome water hammer effect. 04

OR

(c) With neat sketch explain the Renold’s experiment. 04

(d) An oil specific viscosity 0.15 N-s/m2 and specific gravity 0.81 flows through a pipe of 140mm diameter at the flow rate of 0.03 m3/sec. Determine whether flow is laminar or turbulent. 04

OR

(d) Oil flowing through a pipe of 200 mm diameter and 1Km length. If steady discharge is 3 m3/min, calculate head loss due to friction. Take f =0.01. 04

Q.4 (a) Give the classification of turbines. 03

OR

(a) Find the specific speed of turbine and the type of turbine, if total head of is 25m and the power produced is 7.5MW running at 150 rpm. 03

(b) Describe centrifugal pump with neat sketch. 04

OR

(b) A C.F. pump transmits 14.71kw power against the total head of 15m of water. Find the discharge of water in liter/minute, if efficiency of the pump is 72%. 04

(c) Draw a neat sketch of reciprocating pump with air vessels. Explain the importance of air vessel in reciprocating pump. 07

Q.5 (a) Explain the working of following with neat sketch (any two).
(i)Hydraulic accumulator (ii) Hydraulic press (iii) Hydraulic lift 04

(b) Draw the following symbols in pneumatic circuit.
(i)Direction of oil flow (ii) Air compressor (iii) Pressure regulator valve (iv) Accumulator. 04

(c) Name the element use in pneumatic circuit. 03

(d) Write the application of hydraulic cylinders. 03

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