Effect of feed channel width on heat transfer in a rectangular duct with an array of off-set jets

Experimental investigation was carried out to study the heat transfer characteristics in a rectangular duct cooled by an array of impinging jets. Air ejected from an array of orifices is aimed at the heated target surface and exits from the radial outlets. The effect of feed channel widths (5 ≤ H/d ≤ 9), jet to target plate distance (4 ≤ S/d ≤ 8), outflow orientation and jet Reynolds numbers (9300 ≤ Re_j ≤ 18800) with a single array of equally spaced off-set orifice jets of diameter d = 0.5 cm on heat transfer was studied. Results indicated that the outflow orientation causing crossflow effect significantly affects the Nusselt number distributions on the target surface. Relatively higher Nusselt number values were obtained for the outflow orientation where the flow exits in both the directions. The feed channel width H/d = 7 gave relatively higher values of heat transfer compared to the other two feed channel widths. The jet-to-plate distance S/d = 4 resulted in higher heat transfer compared to the other jet-to-plate distances.