Code No: 07A3EC02 Set No. 4

II B.Tech I Semester Regular Examinations, November 2008

FLUID MECHANICS AND HYDRAULIC MACHINERY

( Common to Electrical & Electronic Engineering and Production

Engineering)

Time: 3 hours Max Marks: 80

Answer any FIVE Questions

All Questions carry equal marks

⋆ ⋆ ⋆ ⋆ ⋆

1. (a) Define dynamic viscosity and kinematic viscosity. What are their units? Ex-

plain the significance of viscosity on fluid motion.

(b) Find the pressure in N/m2 represented by a column of

i. 10cm of water

ii. 5 cm of oil of relative density 0.75

iii. 2cm of mercury. [8+8]

2. (a) Derive the equation of continuity in dierential form.

(b) Determine whether the following velocity components satisfy the continuity

equation:

i. u = 2x2 + zy, v = −2xy + 3y3 + 3zy, w = −3/2 z2

− 2xy − 6yz

ii. u = −cx/y, v = c log xy. [6+10]

3. (a) Explain how do you measure the velocity of flowing water in a stream using

pitot tube.

(b) An oil of relative density 0.90 flows through a vertical pipe of diameter 20cm.

The flow is measured by a 20cm × 10cm venturimeter. The throat is 30cm

above the inlet section. A dierential U tube manometer containing mercury

is connected to the throat and the inlet. If coecient of discharge is 0.99 what

is the manometer reading for a flow of 50lit/sec. [6+10]

4. (a) A 15 cm diameter jet of water with a velocity of 20 m/sec strikes a plate

normally. If the plate is moving with a velocity of 8m/sec in the direction of

the jet, calculate the work done per second on the plate and the eciency of

the energy transfer.

(b) Prove that the force exerted by a jet of water on a fixed hemispherical curved

vane when the jet strikes at the centre is F = ρav2 where

ρ = Mass density of water

a = Area of cross section of the jet

v = Velocity of the jet. [8+8]

5. (a) What are valves used in a penstock. Explain with neat sketches, various types

of valves with their suitability under various conditions.

(b) What is intake structures. Explain dierent types with the help of neat

sketches.

[8+8]

6. (a) How will you classify the turbines? Explain

(b) A Pelton wheel is to be designed for the following specifications. Power

=735.75 kW S.P. Head = 200 m, Speed = 800 r.p.m., η0 = 0.86 and jet

diameter is not to exceed one-tenth of the wheel diameter. Determine :

i. Wheel diameter,

ii. The number of jets required, and

iii. Diameter of the jet. Take Cv = 0.98 and speed ratio = 0.45. [16]

7. (a) What is cavitation? How can it be avoided in reaction turbine?

(b) What is governing and how it is accomplished for dierent types of water

turbines?

[8+8]

8. (a) Draw an indicator diagram, considering the eect of acceleration and friction

in suction and delivery pipes. Find an expression for the work done per second

in case of single-acting reciprocating pump.

(b) A single-acting reciprocating pump having a bore of 150 mm and a stroke of

300 mm is raising water to height of 20 m above the sump level. The pump

has an actual discharge of 0.0052 m3/s. The eciency of the pump is 70%. If

the speed of pump is 60 r.p.m. Determine:

i. Theoretical discharge

ii. Theoretical power

iii. Actual power, and

iv. Percentage slip. [8+8]

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ReplyDeletemy id is arun.babber1991@gmail.com