13

14 a)
b)

03000ME302052001

with a velocity of 4.5m/s. The inside is constantly wetted with water so as to
maintain a water film on the inside the surface. Determine evaporation rate per
ന of surface area. Kinematic viscocity =15.6 x 10° m/s , Sc = 0.6, Diffusion
coefficient = 0.26 x 1074 m’/s, density under saturated conditions at 25°C = 0.231
kg/m? ⋅

Derive the expression for mass transfer for the case of isothermal evaporation
from the bottom of a small tube through surrounding stagnant gas.

Discuss the analogy between heat transfer and mass transfer

Estimate the diffusion rate of water from bottom of a test tube 1.5cm in diameter

and 15cm long into dry atmospheric air at 25°C. D = 25.6 x 10 भा2/8

TOK RR

Page 3 of 3

(10)

(5)
(5)