PTU Punjab Technical University B-Tech May 2019 Question Papers 5th Semester Automobile Engineering
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Roll No.
Total No. of Pages : 02
Total No. of Questions : 09
B.Tech.(AE) (2011 Onwards) (Sem.?5)
HEAT TRANSFER
Subject Code : BTAE-503
M.Code : 70486
Time : 3 Hrs. Max. Marks : 60
INSTRUCTION TO CANDIDATES :
1.
SECTION-A is COMPULSORY consisting of TEN questions carrying T WO marks
each.
2.
SECTION-B contains FIVE questions carrying FIVE marks each and students
has to attempt any FOUR questions.
3.
SECTION-C contains T HREE questions carrying T EN marks each and students
has to attempt any T WO questions.
SECTION-A
1. Write briefly :
a. Explain the mechanism of heat transfer in fluids.
b. Write the Fourier's equation of conduction in spherical coordinates.
c. What do you mean by critical thickness of insulation?
d. What do you mean by thermal stresses?
e. What is NTU?
f. Why counter flo www.FirstRanker.com
w heat exchanger is more effective than parallel flow?
g. What do you mean Gray bodies, how they are different from black bodies?
h. What is characteristic length?
i. Which dimensionless number is more significant in turbulent flow?
j. What is Kirchhoff's law?
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SECTION-B
2.
What is thermal diffusivity? Discuss its significance.
3.
Show that the temperature distribution in a plane wall without heat generation is linear.
4.
A black body emits the radiation at 2000K calculate its monochromatic emissive power at
1 m wavelength, wavelength at which emission is maximum and maximum emissive
power.
5.
Derive the relationship for the heat transfer from the fin insulated at tip.
6.
What are Newtonian and non-Newtonian fluids? Give examples.
SECTION-C
7.
The variation in the thermal conductivity of a material is given by K=Ko (l + T + T2),
find the expression for the steady state heat transfer in wall of thickness L maintained at
surface temperatures T1 and T2 (T1 > T2).
8.
Water is evaporated continuously at 100?C in an evaporator by cooling 500 kg of air per
hour from 260?C to 150?C. Calculate the heat transfer surface area and steam evaporation
per hour if liquid enters a 100?C. Take Uo= 46 W/m2K, Cp= 1.005 KJ/Kg.K and hfg = 2257
KJ/Kg(at 100 ?C).
9.
Discuss the various parameters that affects the engine heat transfer.
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NOTE : Disclosure of Identity by writing Mobile No. or Making of passing request on any
page of Answer Sheet will lead to UMC against the Student.
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This post was last modified on 04 November 2019