Rib spacing effect on heat transfer and pressure loss in a rectangular channel with semicircular ribs
Experimentation was conducted to find out the influence of rib spacing on thermal performance in a rectangular channel. Semicircular shape rib was studied for three rib spacing (P/e) = 8, 10 and 12 and located on lower wall of the channel. Reynolds numbers varied from 10000 to 29,000 and the blockage ratio of the channel (e/Dh) was 0.151.Result shows that semicircular rib performed well compared to plain plate, enhanced maximum 130 % heat transfer and 200 % friction. Also heat transfer enhancement was seen maximum at rib spacing of 50 mm (P/e =10), enhanced avg. 39 % heat transfer over rib spacing of 40 and 60 mm (P/e=8 & 12). Friction loss observed more in rib pitch to height ratio of 8, found average 10 % more friction loss compared to rib pitch to height ratio 10 & 12. Semicircular rib with spacing ratio 8 shows least thermal performances compared to other configurations.