Rib spacing effect on heat transfer and pressure loss in a rectangular channel with semicircular ribs

Ribs of various shapes are used for heat transfer enhancement but its performance is significantly depends on geometrical features and flow conditions. This study experimentally find out the influence of rib spacing, semicircular shape ribs with three rib spacing ratio (P/e) = 8, 10 and 12 are studied and located on lower wall of the rectangular channel. Reynolds numbers varied from 10000 to 29,000 and the blockage ratio of the channel (e/Dh) was 0.151.Result show that semicircular rib performed better than plain plate but found more friction. semicircular rib with rib spacing of 50 mm (P/e =10) shows highest thermal performance, enhanced avg. 39 % heat transfer than rib spacing of 40 and 60 mm (P/e=8 & 12). Friction losses observed highest in rib spacing ratio of 8,found average 10 % more friction compared to rib spacing ratio of 10 & 12. Semicircular rib with spacing ratio 8 shows least thermal performances compared to other configurations.