Influence of two-dimensional artificial roughness on convective heat transfer

Abstract

Results are presented of experimental investigation of heat transfer from tubes with two-dimensional artificial roughness elements on their outer surfaces. Removal of heat was accomplished by means of transformer oil and water. The local temperatures of rough surfaces were measured and an attempt made to reveal the mechanism of increase in heat-transfer rate due to two-dimensional roughness. The results are compared with previously existing results, both theoretical and experimental. The experimental data are correlated and an empirical equation is obtained. Experimental data of other authors show good agreement with this equation.