Heat Transfer in Channels Having Rough and Smooth Surfaces

Abstract

The author proposes a method of comparing the heat transfer coefficients in two channels in which

(1) the cross-sectional shape is different;

(2) there are different proportions of rough and smooth surfaces;

(3) there are different proportions of heated and unheated surfaces.

In particular the method applies to experimental results for the system in which a roughened, heated cylinder is placed centrally in a smooth unheated pipe. The effective diameter concept is used to allow for changes in shape, and the heat-transfer boundary conditions are modified to make them similar to the fluid-flow boundary conditions before the comparison is made.