B.E./B.Tech. DEGREE
EXAMINATION, APRIL/MAY 2011
Third Semester
Mechanical
Engineering
ME 2204 — FLUID
MECHANICS AND MACHINERY
(Common to Automobile
Engineering, Production Engineering and
Aeronautical
Engineering)
(Regulation 2008)
Time : Three hours
Maximum : 100 marks
Answer ALL questions
PART A — (10 × 2 = 20
marks)
1. Define surface
tension and expression its unit.
2. What is Darey's
equation? Identify various terms in the equation.
3. What is viscosity
and give its units?
4. Distinguish
between a control and differential control volume.
5. Check whether the
following equation is dimensionally homogeneous.
6. Distinguish
between Rayleigh's method and Buckingham's Π- theorem.
7. Write the Euler's
equation.
8. A shaft transmits
150 Kw at 600 rpm. What is the torque in Newton –metres?
9. Why is the
reciprocating pump called a positive displacement pump?
10. What is a rotary
pump? Give its classification.
PART B — (5 × 16 = 80
marks)
11. (a) Explain in
detail the Newton's law of viscosity. Briefly classify the fluids based on the
density and viscosity. Give the limitations of applicability of Newton's law of
viscosity. (16)
Or
(b) State the law of
conservation of man and derive the equation of continuity in Cartesian
coordinates for an incompressible fluid. Would it alter if the flow were
unsteady, highly viscous and compressible?
12. (a) A lubricating
oil flows in a 10 cm diameter pipe at 1 m/s. Determine whether the flow is
laminar or turbulent. For the lubricating oil μ = 0.1Ns2 /m and ρ =
930 kg/m3. Calculate also transition and
turbulent velocities.
Or
(b) A smooth flat
plate with a sharp leading edge is placed along a free stream of water flowing
at 3m/s. Calculate the distance from the leading edge and the boundary
thickness where the transition from
laminar to turbulent-
flow may commence. Assume the density of water as 1000 kg/m3 and
viscosity as 1 centipoise.
13. (a) What is the
significance and the role of the following parameters?
(i) Reynolds number
(ii) Froude number
(iii) Mach number
(iv) Weber number.
(16)
Or
(b) An agitator of
diameter D rotates at a speed N in a liquid of density ρ and
viscosity μ
. Show that the power required to mix the liquid is expressed by a
functional form
14. (a) A gas turbine
operates between 1000k and 650 k temperature limits taking in air 20 kg/s at
125 m/s and discharging at 300 m3/s. Estimate
the power developed by the turbine. Given C p =995 J
/ Kg.K .
Or
(b) Explain in detail
about the performance curves for pumps and turbines.
(16)
15. (a) A single
acting reciprocatory pump has a plunger of diameter 30 cm and stroke of 20 cm.
If the speed of the pumps is 30 rpm and it delivers to 6.5 lit/s of water, find
the coefficient of discharge and the percentage slip of the pump.
Or
(b) Write briefly on
the following.
(i) Rotary pumps and
their classifications. (8)
(ii) Indicator
diagram for reciprocating pump. (8)