Effect of Rib Profiles on Turbulent Channel Flow Heat Transfer

Introduction R EPEATED ribs have been used as the promoters of turbulence to enhance the heat transfer to the  ow of coolants in channels. Several publications have addressed the comprehensive review of turbine blade cooling and the analysis of heat transfer and friction characteristics of  ow in channels with two opposite rib-roughened walls. The effects of  ow Reynolds number and rib geometry (rib height e, rib spacing P, rib angle of attack a, and rib orientation) on heat transfer and pressure drop in the fully developed region of square, rectangular, and triangular channels have been investigated. 4 Semiempirical correlations over a wide range of rib geometry for the friction and heat transfer design calculations are derived from the law-of-the-wall similarity for  ow over rough surfaces. A detailed analysis of the application of the similarity laws in the case of rectangular channels is presented by Han. Also, studies of the effect of a number of channel-ribbed walls on heat and friction characteristics have been reported. Experiments with some nonrectangular rib shapes have been reported. The previously mentioned studies were limited in the number of rib shapes and were for different conditions (rib height to channel hydraulic diameter ratio e/Dh, and Reynolds number Re). This study focuses on the effect of different rib proŽ les on turbulent channel  ow heat transfer and friction characteristics.