An investigation of heat transfer and friction for rib-roughened surfaces

An investigation of rib-roughened surface was undertaken to determine the effects of rib shape, angle of attack and pitch to height ratio on friction factor and heat-transfer results. A parallel plate geometry was used. Based on the law of the wall similarity and the application of the heat-momentum analogy developed by Dipprey and Sabersky, a general correlation for friction factor and heat transfer was developed to account for rib shape, spacing and angle of attack. Ribs at 450 angle of attack were found to have superior heat transfer performance at a given friction power when compared to ribs at a 900 angle of attack or when compared to sand-grain roughness. (author)