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Register No.:
QP. No: V15/9308
Sub Code: 15CBME42
(For Candidate admitted from 2015 – 16 & 2016 -17)
B.E., Degree Examinations, May 2018
MECHANICAL ENGINEERING
Second Year – Fourth Semester
FLUID MECHANICS AND MACHINERY
Time : Three Hours.
M ax Marks.100
SECTION – A
Answer all questions
(10 x 2 = 20)
1. Define dynamic viscosity.
2. Define specific volume.
3. Define Steady and Unsteady flow.
4. State the assumptions used in deriving Bernoulli’s equation.
5. Define model and prototype.
6. Define kinematic similarities.
7. What is a reciprocating pump?
8. What is single acting pump and double acting pump?
9. Define Mechanical efficiency.
10. Define Jet Ratio.
SECTION – B
Answer the following
(5 x 16 = 80)
11. (a) Determine the power required to run a 300 mm dia shaft at
400 rpm in journals with uniform oil thickness of 1 mm.
Two bearings of 300 mm width are used to support the shaft.
(OR)
(b) A small thin plane surface is pulled through the liquid filled
space between two large horizontal planes in the parallel
direction. Show that the force required will be minimum if
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the plate is located midway between the planes.
12. (a) What do you understand by the terms?
(i) Major energy losses (ii) Minor energy losses.
(OR)
(b) Derive an expression for loss of head due to sudden
enlargement of the pipe.
13. (a) Efficiency η of a fan depends on the density ρ, the dynamic
viscosity of the fluid µ, the angular velocity ω, diameter D of
the rotor and the discharge Q. Express in terms of
dimensional parameters.
(OR)
(b) The resistance force R of a supersonic plane during flight
can be considered as dependent upon the length of the
aircraft l, velocity v, air viscosity µ, air density ρ and bulk
modulus of air K. Express the functional relationship
between these variables and the resisting force.
14. (a) At a location for a hydroelectric plant, the head available
(net) was 335 m. The power availability with an overall
efficiency of 86% was 15500 kW. The unit is proposed to run
at 500 rpm. Assume Cv = 0.98, φ = 0.46, Blade velocity
coefficient is 0.9. If the bucket outlet angle proposed is 165°
check for the validity of the assumed efficiency.
(OR)
(b) A Francis turbine works under a head of 120 m. The outer
diameter and width are 2 m and 0.16 m. The inner diameter
and width are 1.2 m and 0.27 m. The flow velocity at inlet is
8.1 m/s. The whirl velocity at outlet is zero. The outlet blade
angle is 16°. Assume ηH = 90%. Determine, power, speed and
blade angle at inlet and guide blade angle.
15. (a) Explain the following:
(i) Gear Pump (ii) Vane pump.
(OR)
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(b) A single acting reciprocating pump has a bore of 200 mm
and a stroke of 350 mm and runs at 45 rpm. The suction head
is 8 m and the delivery head is 20 m. Determine the
theoretical discharge of water and power required. If slip is
10%, what is the actual flow rate.
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