Andhra University 2009-2nd Year B.E ./B.Tech s FLUID MECHANICS

II Year B.E./B.Tech Degree exams
FLUID MECHANICS & HYDRAULIC MACHINES
Electrical & Electronics Engineering
Time : 3 hours Maximum : 75 Marks
ques. one is compulsory
ans any 4 from ques. two to 8
All ques. carry equal marks
1. ans the subsequent briefly. every bit carries three marks.
a) A glass tube is of internal diameter 6mm is dipped in a trough
containing water. If the surface tension of water is 0.073N/
m and angle of contact is 00 ,what will be the capillary rise
in the tube?
b) compute the unknown velocity component in the following,
2–D flow, so that the formula of continuity is satisfied?
u = Aln (x / L) : v = ?
c) What is the relation ranging from the total energy, velocity head,
pressure head and datum.
d) A compound piping system consists of 1800 m of 50
cm,1200m of 40cm and 600 m of 30cm pipes of the identical
material connected in series. What is the equivalent size of
the pipe of 3600 m long?
e) Distinguish ranging from Impulse and reaction turbines.
2. a) describe kinematic viscosity. elaborate its dimensions and units
in SI system? (4 Marks)
b) A circular disc of radius 'R' rotates at an angular velocity
'w ' , maintaining a small distance 'h' above a fixed bed under
the support of a fluid layer of viscosity is 'm ' .Obtain the
23
expression for the torque on the disc. (7 Marks)
c) describe centre of pressure. (4 Marks)
3 a) describe local, convective and total accelerations (4 Marks)
b) Derive continuity formula in 3 dimensional Cartesian
coordinates. (6 Marks)
c) Draw the sketch of a prandtl kind of Pitot tube along with
the pressure measuring device. (5 Marks)
4. a) Derive Bernoulli formula through integration of Eulers
formula for irrotational flow. elaborate the assumptions?
(7 Marks)
b) An oil of sp.gr.0.90 flows through a vertical pipe of diameter
20 cm. The flow is measured by a 20cm x 10cm
venturimeter. The throat is 10cm above the inlet. A differential
U-tube mercury manometer is connected to the Venturimeter.
If Cd = 0.09 , what is (a) the flow for a manometer studying
of nine cm and (b) the manometer studying for a flow of 50
1ps? (8 Marks)
5. a) Distinguish ranging from the energy principle and momentum
principle with reference to their application to practical
problems. (5 Marks)
b) A reducer bend having an outlet diameter of 15 cm discharges
freely. The bend connected to a pipe of 20 cm diameter, has
a deflection of 600 and lies in a horizontal plane. Determine
the magnitude and direction of force on the anchor block
supporting the pipe when a discharge of 0.3m3 / s is passing
through the pipe. (6 Marks)
c) Show that the coefficient of discharge for an orifice is equal
to the product of the coefficient of velocity and coefficient of
contraction. (4 Marks)
24
6. a) Derive the condition for maximum transmission of power
through a nozzle fitted at the end of a pipe (5 Marks)
b) Water is discharged from a reservoir into the atmosphere
through a pipe 39m long. There is a sharp entrance to the
pipe and the diameter is 50 mm for 15 m from the entrance.
The pipe then enlarges suddenly to 75 mm in diameter for
the reminder of its length. Taking into account the loss of
head at entry, enlargement, compute the difference of level
ranging from the water surface of the reservoir and the pipe exit
which will maintain a flow of 2.8 1ts/sec. Take f = 0.02 for
50 mm pipe and 0.025 for 75 mm pipe. Draw also HGL
and total energy gradient lines. (6 Marks)
c) discuss the function of Surge tanks. List the different kinds of
Surge tanks. (4 Marks)
7. a) find the expression for the work done by water that strikes
a series of curved vanes mounted on a wheel. (6 Marks)
b) In a single acting reciprocating pump, the cylinder has a
diameter of 150 mm and a stroke of 300mm. The water is
to be raised to a height of 20m when the pump is running at
40 rpm. Determine the theoritical discharge and theoritical
H.P. If the true discharge of the pump is 3.5 Ips, obtain
coefficient of discharge and % slip. (5 Marks)
c) find an expression for the minimum starting speed of a
centrifugal pump. (4 Marks)
8. a) Draw a neat sketch of Pelton turbine showing its main
component parts and then discuss their function in detail
(7 Marks)
b) A Francis turbine is fitted with a vertical conical shaped draft
tube. The top and botton diameters of draft tube are 60 cm
and 90 cm respectively. The tube is running full with water
25
and it has a vertical height of six m out of which 1.5 m is
drowned in the tail race water. presume that the friction loss
of head ranging from top and bottom points as 0.3 times kinetic
head at the draft tube exit. The velocity of exit is 1.5 m/s.
Determine (i) the pressure head at the top point of draft
tube, (ii) the total head at the identical point with reference to
the tail race as datum, (iii) the total head of the bottom point
with tail race as datum, (iv) the power in the water at the top
and bottom of the tube and (v) efficiency of the draft tube.
(8 Marks)

Earning:   Approval pending.