RGPV Previous Year Question Papers - HMT

Heat and Mass transfer


 Question.01

 (a) What is thermal resistance ?

  (b) Express the thermal resistance for conduction for a hollow cylinder in terms of inner and outer radii.

Question.02

A domestic oven has a composite wall formed by 0.5 cm thick chrome nickel (k= 19w/mK) sheet supported by 1cm thick asbestos (k = 0.1105 W/mK) sheet. In steady state operation the hot gases inside the oven are at 350℃ while atmospheric air is at 30℃ . The convective heat transfer coefficient at inside and outside surface of the oven are 100 W/m2K and 15W/m2K respectively. Determine the rate of heat losses per unit area through the oven wall.

Question.03

(a) What is an extended surface ? Name three application of it.
(b) Define fin efficiency and fin effectiveness.

Question.04

(a) Distinguish between natural and forced convection.
(b) What is Grashof number and Rayleigh number ? Discuss the significance.

Question.05

A Horizontal rod of 5cm diameter is maintained at a constant temperature of 70℃ by submerging it in water of 20℃ . Calculate the heat loss by free convection per unit length of rod.

Question.06

Define LMTD and derive it's expression for parallel flow heat exchanger.

Question.07

(a) What is thermal radiation ? State the governing heat transfer law of radiation.
(b) Explain the different regimes of boiling.

Question.08

(a) Critical thickness
(b) Fick's law of mass transfer
(c) Black and gray surface.
(d) Filmwis condensation.