JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD

JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD B.Tech II FLUID MECHANICS AND HEAT TRANSFER Previous Question Paper (April/May - 2023 - R16)

B.Tech | II | II | R16 | April/May - 2023

Answer PaperPaper Code: 134BBMaximum Marks: 75Time: 3 Hours

Note: i) Question paper consists of Part A, Part B. ii) Part A is compulsory, which carries 25 marks. In Part A, Answer all questions. iii) In Part B, Answer any one question from each unit. Each question carries 10 marks and may have a, b as sub questions.

PART - A

125 marks
a
State the condition for Irrotational flow.
2 marks

Answer

A flow is considered irrotational if the vorticity vector is zero at every point in the flow field. Mathematically, this is expressed as the curl of the velocity vector being zero: ∇ × V = 0. In Cartesian coordinates, this implies that the angular velocity components about the x, y, and z axes are all zero.

b
Classify different types of flows with example.
3 marks

Answer

Flows are classified based on time and space variations:

  • Steady and Unsteady flow: Steady flow properties do not change with time (e.g., flow through a pipe at constant discharge). Unsteady flow properties change with time (e.g., flow during pipe start-up).
  • Uniform and Non-uniform flow: Uniform flow velocity does not change with location (e.g., flow through a constant diameter pipe). Non-uniform flow velocity changes with location (e.g., flow through a tapering pipe).
  • Laminar and Turbulent flow: Laminar flow involves fluid particles moving in smooth layers (e.g., oil flow in a capillary). Turbulent flow involves chaotic, eddy-driven motion (e.g., high-velocity flow in a river).
c
Derive momentum equation.
2 marks

Answer

Sign in to view the complete answer paper.

d
Write the expressions for cv, cc and cd for an orifice.
3 marks

Answer

Sign in to view the complete answer paper.

e
Define conduction.
2 marks

Answer

Sign in to view the complete answer paper.

f
Explain different modes of heat transfer.
3 marks

Answer

Sign in to view the complete answer paper.

g
Define Euler number and Weber number.
2 marks

Answer

Sign in to view the complete answer paper.

h
Explain about maximum and minimum heat dissipation.
3 marks

Answer

Sign in to view the complete answer paper.

i
Define gray body.
2 marks

Answer

Sign in to view the complete answer paper.

j
With a neat sketch, explain parallel flow heat exchanger.
3 marks

Answer

Sign in to view the complete answer paper.

PART - B

210 marks
a
Define and distinguish between streamline, path line and streak line.
5 marks

Answer

Sign in to view the complete answer paper.

b
The flow field is given by ψ = x3y. Check whether the given field exists or not? Further check whether it is irrotational?
5 marks

Answer

Sign in to view the complete answer paper.

OR
310 marks
a
Define and distinguish between (i) steady and unsteady flow (ii) uniform and non-uniform flow (iii) rotational and irrotational flow.
5 marks

Answer

Sign in to view the complete answer paper.

b
Determine whether the following velocity components satisfy the continuity equation. i) u = cx, v = -cy ii) u = -cx/y, v = c log xy.
5 marks

Answer

Sign in to view the complete answer paper.

410 marks
a
Write Euler’s equation of motion. State the Bernoulli’s equation and write the assumption made in it. How is it modified while applying in practice.
5 marks

Answer

Sign in to view the complete answer paper.

b
A pipe through which water is flowing, is having diameters, 20cm and 10cm at the cross-sections 1 and 2 respectively. The velocity of water at section 1 is given as 4 m/s. Find the velocity head at sections 1 and 2 and also rate of discharge.
5 marks

Answer

Sign in to view the complete answer paper.

OR
510 marks
a
What are the surface and body forces associated with fluid flow? How are they incorporated in Euler’s equation?
5 marks

Answer

Sign in to view the complete answer paper.

b
A 30-cm diameter horizontal pipe terminates in a nozzle with the exit diameter of 7.5 cm. If the water flows through the pipe at the rate of 0.15 m3/s. What force will be exerted by the fluid on the nozzle?
5 marks

Answer

Sign in to view the complete answer paper.

610 marks
a
Derive the general heat conduction equation in Cartesian coordinates.
5 marks

Answer

Sign in to view the complete answer paper.

b
A large slab of aluminium at a uniform temperature of 200°C suddenly has its surface temperature lowered to 70°C. What is time when the temperature at a depth 4 cm has dropped to 120°C.
5 marks

Answer

Sign in to view the complete answer paper.

OR
710 marks
a
What is critical radius? Why it is necessary? Derive expression of critical radius for Spherical shape.
5 marks

Answer

Sign in to view the complete answer paper.

b
A wall of 0.5 m thickness is to be constructed of a material which has an average thermal conductivity of 1.4 W/mK. The wall is to be insulated with a material having a thermal conductivity of 0.35 W/mK. Heat loss/m2 is not to exceed 450W. Assuming that the inner and outer surface temperatures are 1200°C and 15°C calculate the thickness of insulation required.
5 marks

Answer

Sign in to view the complete answer paper.

810 marks
a
Explain the development of velocity and thermal boundary layers for flow over a flat plate.
5 marks

Answer

Sign in to view the complete answer paper.

b
Calculate the convective heat transfer from a radiator 0.5m wide and 1m high at 84°C in a room at 20°C. Treat the radiator as a vertical plate.
5 marks

Answer

Sign in to view the complete answer paper.

OR
910 marks
a
Air at 20°C at 3m/s flows over a thin plate of 2m long and 1m wide at 100°C. Estimate the boundary layer thickness at the trailing edge, total drag force, mass flow of air between x = 30cm and x = 80 cm. Also, calculate heat transferred. Take viscosity = 15 × 10-6 kg/ms and density = 1.17 kg/m3.
8 marks

Answer

Sign in to view the complete answer paper.

b
Write about Colburn’s analogy.
2 marks

Answer

Sign in to view the complete answer paper.

1010 marks
a
What is fouling in heat exchangers? How is it specified?
5 marks

Answer

Sign in to view the complete answer paper.

b
Explain Plate type heat exchanger with its advantage and disadvantage.
5 marks

Answer

Sign in to view the complete answer paper.

OR
1110 marks
a
A furnace is approximated as an equilateral triangular duct of sufficient length so that end effects can be neglected. The hot wall of the furnace is maintained at 900 K and has an emissivity of 0.8. The cold wall is at 400 K and has the same emissivity. Find the net radiation heat flux leaving the wall. Third wall of the furnace may be assumed as a reradiating surface.
5 marks

Answer

Sign in to view the complete answer paper.

b
An enclosure measures 1.5m × 1.5m with a height of 2m under steady state conditions. The wall and ceiling are maintained at 525 K and floor is at 400K. Determine net radiation to floor. Take emissivity of ceiling and wall = 0.85 and emissivity of floor = 0.75.
5 marks

Answer

Sign in to view the complete answer paper.

About this paper

This page contains the question paper of FLUID MECHANICS AND HEAT TRANSFER from JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD for B.Tech MECT-MCT-MEM II II, April/May - 2023, R16.

For the solved question paper with answers, switch to the Answer Paper tab.

Other papers in FLUID MECHANICS AND HEAT TRANSFER

Loading Question Papers

Fetching data from database...