Download GTU (Gujarat Technological University) BE/BTech (Bachelor of Engineering / Bachelor of Technology) 2019 Summer 6th Sem Old 160202 Automobile Heat Transfer Previous Question Paper
Seat No.: ________ Enrolment No.___________
GUJARAT TECHNOLOGICAL UNIVERSITY
BE - SEMESTER ?VI(OLD) ? EXAMINATION ? SUMMER 2019
Subject Code:160202 Date:29/05/2019
Subject Name: Automobile Heat Transfer
Time:10:30 AM TO 01:00 PM Total Marks: 70
Instructions:
1. Attempt all questions.
2. Make suitable assumptions wherever necessary.
3. Figures to the right indicate full marks.
Q.1 (a) Derive an expression for one-dimensional steady-state heat conduction
from composite wall with three layers.
07
(b) Discuss the various regimes of boiling and explain the condition for the growth
of bubbles.
07
Q.2 (a)
Explain the significance of fin efficiency and effect of Biot number on fin
effectiveness.
07
(b)
Explain the circumstances under which natural convection occurs. Differentiate
between natural and forced convection.
07
OR
(b) Derive Von-Karman integral momentum equation for hydrodynamic boundary
layer over a flat plate.
07
Q.3 (a) State and explain Wien?s displacement law. 07
(b) A wire of 6.5mm diameter at a temperature of 60
o
C is to be insulated by a
material having k=0.174W/m
o
C.Convection heat transfer coefficient
(ho)=8.722W/m
2o
C.The ambient teparature is 20
o
C.For maximum heat loss,
what is the minimum thickness of insulation and heat loss per meter length?
Also find % increase in heat dissipation too.
07
OR
Q.3 (a) Briefly explain the significance of following dimensionless numbers.
Reynolds number and Prandtl number.
07
(b) Explain heat exchanger effectiveness, fouling and NTU.
07
Q.4 (a) Write a short note on heat pipe stating principle of operation, types and
applications.
07
(b) Explain with a neat sketch construction of a radiator.
07
OR
Q.4 (a) Discuss the modes of condensation. Why dropwise condensation is preferred? 07
(b) Assuming the sun to be a black body having a surface temperature of
5800K,calculate (a) the total emissive power,(b) the wavelength at which the
maximum spectral intensity occurs,(c) the maximum value of Eb?,(d) the total
amount of radiant energy emitted by the sun per unit time if its diameter can be
assumed to be 1.391 x 10
9
m.
07
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1
Seat No.: ________ Enrolment No.___________
GUJARAT TECHNOLOGICAL UNIVERSITY
BE - SEMESTER ?VI(OLD) ? EXAMINATION ? SUMMER 2019
Subject Code:160202 Date:29/05/2019
Subject Name: Automobile Heat Transfer
Time:10:30 AM TO 01:00 PM Total Marks: 70
Instructions:
1. Attempt all questions.
2. Make suitable assumptions wherever necessary.
3. Figures to the right indicate full marks.
Q.1 (a) Derive an expression for one-dimensional steady-state heat conduction
from composite wall with three layers.
07
(b) Discuss the various regimes of boiling and explain the condition for the growth
of bubbles.
07
Q.2 (a)
Explain the significance of fin efficiency and effect of Biot number on fin
effectiveness.
07
(b)
Explain the circumstances under which natural convection occurs. Differentiate
between natural and forced convection.
07
OR
(b) Derive Von-Karman integral momentum equation for hydrodynamic boundary
layer over a flat plate.
07
Q.3 (a) State and explain Wien?s displacement law. 07
(b) A wire of 6.5mm diameter at a temperature of 60
o
C is to be insulated by a
material having k=0.174W/m
o
C.Convection heat transfer coefficient
(ho)=8.722W/m
2o
C.The ambient teparature is 20
o
C.For maximum heat loss,
what is the minimum thickness of insulation and heat loss per meter length?
Also find % increase in heat dissipation too.
07
OR
Q.3 (a) Briefly explain the significance of following dimensionless numbers.
Reynolds number and Prandtl number.
07
(b) Explain heat exchanger effectiveness, fouling and NTU.
07
Q.4 (a) Write a short note on heat pipe stating principle of operation, types and
applications.
07
(b) Explain with a neat sketch construction of a radiator.
07
OR
Q.4 (a) Discuss the modes of condensation. Why dropwise condensation is preferred? 07
(b) Assuming the sun to be a black body having a surface temperature of
5800K,calculate (a) the total emissive power,(b) the wavelength at which the
maximum spectral intensity occurs,(c) the maximum value of Eb?,(d) the total
amount of radiant energy emitted by the sun per unit time if its diameter can be
assumed to be 1.391 x 10
9
m.
07
2
Q.5 (a) Derive the expression for fin efficiency for a fin insulated at the tip.
07
(b) In a counter flow heat exchanger,flue gases at 800
o
C(Cp = 1.1kJ/kgK) with flow
rate of 4kg/sec.The air on other side is flowing with 6 kg/sec at 400
o
C inlet
tempwrature and 551.5
o
C at outlet.Take U = 100W/m
2
k. Determine: (a) heat
transfer area needed and (b) NTU
07
OR
Q.5 (a) Derive the expression for LMTD for parallel flow heat exchangers.
07
(b) What is a radiation shield? When it is used? Also write the expression for
radiation heat transfer between two parallel plates with one shield.
07
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This post was last modified on 20 February 2020