International Journal of Engineering and Technology

the work reported in this paper is a systematic experimental heat transfer and pressure drop comparison between smooth and three different sized square ribbed divergent rectangular ducts. The ribs are attached at an inclination angle of 1° in the y-direction in a test section. The heights of the rib turbulators (e) were 3, 6 and 9 mm. This yields an rib height (e) to mean hydraulic diameter of the duct (Dm) ratio of 0.035, 0.0697 and 0.1046 respectively with a fixed rib pitch (p) to test section inlet width (w) ratio of 0.6, and to maintained identical mass flow rate. The results obtained from the ribbed ducts were compared with that of the same parameter smooth (without ribs) divergent rectangular duct. The enhanced heat trnasfer rate for the 3 mm height rib divergent rectangular duct is more than the 6, 9 mm rib height rectangular convengent duct and smooth duct. In terms of pressure drop 9 and 6 mm rib height is higher than 3 mm and smooth duct respectively.