1(a) Write a note on respiratory
gas exchange in lungs (6 Marks)

(b) Differentiate between thermal
conductivity and thermal diffusivity. (6 Marks)

(c) Explain why a quilt is a
better insulator than a woolen blanket of the same thickness. (4 Marks)

(d) Identify the heat transfer
processes that determine the temperature on the inside of a room on a hot
summer day. (4 Marks)

2(a)What is Biot number? Explain
its significance. (4 Marks)

(b) What are Fins? Explain in
detail transfer of heat from pin-fins of constant cross-section. (8 Marks)

(c) Write a note on thermal
sterilization of canned goods. (4 Marks)

(d) A 200 g slab of butter at 300
K is put in a refrigerator at 277K. It takes 120 minutes for the centre of the
slab to reach 281K. How long would it take for the centre of the slab to reach
279K? (4 Marks)

3(a) Using a neat figure, explain
nodal mesh. (6 Marks)

(b) Explain method of energy
balance for an interior node. (8 Marks)

(c) A 4mm brass plate is
initially at 0

^{0}C. One side of the plate is suddenly brought to a temperature of 100^{0}C, with the other side maintained at 0^{0}C. Develop a finite difference formulation for obtaining the temperature distribution across the plate for various times. (6 Marks)
4(a) What is transpiration
cooling? Write a note on reduction of evaporative losses in liquid nitrogen
flask by transpiration. (10 Marks)

(b) State and explain Reynolds
transport theorem. (6 Marks)

(c) Find the rate of heat
transfer from a spherical water tank of diameter 10m, when exposed to quiescent
air at 20

^{0}C, when its surface temperature is 35^{0}C. (4 Marks)
5 (a) With special relevance to
velocity profile and temperature profile, explain heat transfer in Couette flow.
(6 Marks)

(b) Deduce the governing
equations for free convection flows. (6 Marks)

(c) Explain why the surface of a
bridge always freezes faster than the surface of a road. (4 Marks)

(d) Saturated steam at 54

^{0}C condenses on a 2cm diameter vertical tube of length 1m with the surface temperature of 40^{0}C. Determine the rate of condensation of stem assuming film condensation. (4 Marks)
6 (a) What is free molecular
transfer? Explain. (6Marks)

(b) Explain Fick law. (4 Marks)

(c) A mixture of inert gases
contains equal mass fractions of helium, argon and xenon. Determine the
composition in terms of the mole fractions. (4 Marks)

(d) Calculate the fraction of
gases remaining at the centre of a 1cm thick slab of steel after 10 hours of
vacuum out-gassing treatment. Assume the initial distribution of gas in steel
to be uniform and diffusivity to be 10

^{-9}m^{2}/s. (6 Marks)
7 (a) Write a note on absorption
of gas by a falling film of liquid. (8 Marks)

(b) Consider a turbulent flow
over a flat plate. Determine the percentage change in the mass transfer rate,
if the Schmidt number is halved by (a) reducing the viscosity by a factor of
two, or (b) doubling the binary diffusivity. (6 Marks)

(c) Sketch the temperature versus
length curves for a counter-flow and a parallel-flow heat exchanger for the
case when C

_{c}= C_{h}. (6 Marks)
8(a) What is a blackbody?
Calculate the total emission from a black surface in terms of intensity of
radiation. (6 Marks)

(b) What is configuration factor?
Explain the role of reciprocity relation in the evaluation of configuration
factors. (6 Marks)

(c) An isothermal furnace with a
small hole is used to calibrate radiometric devices. If the radiation intensity
is to lie within 0.5% of the nominal, determine the allowable variation in the
temperature of the furnace when it is operating at 300K. (4 Marks)

(d) Consider two concentric
spheres, 25 and 50 mm in diameter. The outer surface of the inner sphere is a
blackbody and is at 1000K, while the inner surface of the outer sphere is gray
with emissivity of 0.8 and is at a temperature of 500K. Determine the radiative
exchange between the two surfaces. (4 Marks)

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