Code No: 07A3EC02 Set No. 3

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) What are the absolute and kinematic viscosities? Derive the equations for

them. Discuss what factors will influence them.

(b) Estimate the pressure inside a water droplet of size of 0.3mm. Assume σ=0.073N/m.

[10+6]

2. (a) What is the criteria to distinguish rotational flow from irrotational flow?

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

equation.

i. u = A sin xy, v = −A sin xy

ii. u = x + y, v = x − y. [6+10]

3. (a) Dierentiate between stagnation pressure head and static pressure head with

reference to a pitot tube. Explain with the help of a neat sketch.

(b) A venturimeter of throat diameter 5cm is fitted into a 12.5 cm diameter water

pipe line. The coecient of discharge is 0.96. Calculate the flow in the pipe line

when the reading on a mercury water dierential U tube manometer connected

to the upstream and throat sections shows a reading of 20 cm. [6+10]

4. (a) A 15 cm diameter jet of water strikes a curved vane with a velocity of 40m/sec.

The inlet angle of the vane is zero and the outlet angle is 30 degrees. Calculate

the resultant force on the vane when it is moving with a velocity of 12m/sec

in the direction of the jet.

(b) State the equation used to find out the impact of jet on vanes. Derive the

equation for resultant thrust when a jet strikes a stationary inclined flat plate.

[8+8]

5. (a) What is a run o river plant. What are the dierent parts and arrangements

of such plants? Draw a neat sketch and explain

(b) What is meant by flow duration curve and power duration curve. How do you

dierentiate these two curves? Also explain power duration curve in detail.

[8+8]

6. (a) Dierentiate between:

i. The impulse and reaction turbines,

ii. Radial and axial flow turbines,

Code No: 07A3EC02 Set No. 3

iii. Inward and outward radial flow turbine, and

iv. Kaplan and propeller turbines.

(b) A Pelton wheel is having a mean bucket diameter of 0.8 m and is running at

1000 r.p.m. The net head on the Pelton wheel is 400 m. If the side clearance

angle is 150 and discharge through nozzle is 150 litres/s, find:

i. Power available at the nozzle, and

ii. Hydraulic eciency of the turbine. [16]

7. (a) By means of a neat sketch explain the governing mechanism of Francis Turbine.

(b) A Hydraulic turbine is to develop 845.6 kW when running at 100 r.p.m. under

a head of 10 m. Work out the maximum flow rate and specific speed for the

turbine if the overall eciency at the best operating point is 92 percent. In

order to predict its performance, a 1:10 scale model is tested under a head of

6 m. What would be the speed, power output and water consumption of the

model if it runs under the conditions similar to the prototype? [8+8]

8. (a) What is the eect of acceleration in suction and delivery pipes on indicator

diagram? Does the area of the indicator diagram change as compared to the

area of ideal indicator diagram?

(b) A centrifugal pump impeller whose external diameter and width at the outlet

are 0.8 m and 0.1 m respectively is running at 550 r.p.m. The angle of impeller

vanes at outlet is 40. The pump delivers 0.98 m3 of water per second under an

eective head of 35 m. If the pump is driven by a 500 kW motor, determine:

i. The manometric eciency

ii. The overall eciency, and

iii. The mechanical eciency. Assume water enters the vanes radially at inlet.

[8+8]

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