Download GTU BE/B.Tech 2019 Winter 6th Sem Old 161906 Heat And Mass Transfer Question Paper

Download GTU (Gujarat Technological University) BE/BTech (Bachelor of Engineering / Bachelor of Technology) 2019 Winter 6th Sem Old 161906 Heat And Mass Transfer Previous Question Paper

1
Seat No.: ________ Enrolment No.___________

GUJARAT TECHNOLOGICAL UNIVERSITY

BE - SEMESTER ? VI (Old) EXAMINATION ? WINTER 2019
Subject Code: 161906 Date: 17/12/2019

Subject Name: Heat And Mass Transfer

Time: 02:30 PM TO 05:00 PM Total Marks: 70

Instructions:

1. Attempt all questions.

2. Make suitable assumptions wherever necessary.

3. Figures to the right indicate full marks.
4. Use of gas and steam tables are permitted.

Q.1 (a) Derive general heat conduction equation in cylindrical co-ordinates with figure 07
(b) Derive equation of critical thickness of insulation. Explain its significance. 07

Q.2 (a) Derive equations of temperature distribution and heat dissipation for fin non-
insulated at tip
07
(b) The walls of a house in cold region consists of three layers- an outer brick work,
15 cm thick, an inner wooden panel, 1.2 cm thick, the intermediate layer is made
of an insulating material, 7cm thick. The thermal conductivities of brick and wood
used are 0.7 W/m-K and 0.18 W/m-K, respectively. The inside and outside
temperature of composite wall are 21
0
C and -15
0
C, respectively.
If the layer of insulation offers twice the thermal resistance of the brick wall,
calculate (i) the rate of heat loss per unit area of the wall, and (ii) thermal
conductivity of insulating material.
07
OR
(b) Explain fin efficiency and fin effectiveness related to thermal performance of fins. 07

Q.3 (a) State and derive Wien?s Displacement Law. 07
(b) Air velocity of 3m/s and at 20
0
C flows over a flat plate along its length. The
length width and thickness of the plate are 100 cm, 50 cm and 2 cm respectively.
The top surface of the plate is maintained at 100
0
C. Calculate the heat lost by the
plate and temperature of bottom surface of the plate for the steady state
conditions. Take kplate = 23 W/m-K.
07
OR
Q.3 (a) Derive Von Karman integral equation for momentum transfer in laminar
boundary layer.
07
(b) What is boiling? Explain pool boiling regimes. 07

Q.4 (a) Explain film wise and drop wise condensation. 07
(b) Define the following in relation with mass transfer
(i) Schmidt number (ii) Lewis number (iii) Sherwood number
07
OR
Q.4 (a) State and explain Fick?s law of diffusion. Express Fick?s law in terms of
partial pressures of gases
07
(b) How are the heat exchangers classified? 07

Q.5 (a) Write short note on heat pipe. 07
(b) Derive LMTD equation for parallel flow heat exchanger 07
OR
Q.5 (a) Describe the phenomenon of radiation from real surfaces. 07
(b) Derive equation of heat transfer with radiation shield between two surfaces. 07

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