Page 341 - Modelling in Transport Phenomena A Conceptual Approach

PROBLEMS 321

Cussler, E.L., 1997, Diffusion - Mass Transfer in Fluid Systems, 2nd Ed., Cambridge
University Press, Cambridge.

Fahien, R.W., 1983, Fundamentals of Transport Phenomena, McGraw-Hill, New
York.

Incropera, F.P. and D.P. DeWitt, 1996, Fundamentals of Heat and Mass Transfer,
4th Ed., Wiley, New York.

Middleman, S., 1998, An Introduction to Mass and Heat Transfer - Principles of
Analysis and Design, Wiley, New York.

PROBLEMS

8.1 When the ratio of the radius of the inner pipe to that of the outer pipe is
close to unity, a concentric annulus may be considered to be a thin plate slit and its
curvature can be neglected. Use this approximation and show that Eqs. (8.1-12)
and (8.1-15) can be modified as

&= mR2V(1 - K~)
2
to determine the velocity distribution and volumetric flow rate for Couette flow in
a concentric annulus with inner and outer radii of KR and R, respectively.

8.2 The composite wall shown below consists of materials A and B with thermal
conductivities k~ = 10 W/ m. K and kg = 0.8 W/ m. K. If the surface area of the
wall is 5 m2, determine the interface temperature between A and B.

I-z
(Answer: 39 "C)