An experimental study was completed to quantify heat transfer enhancement, pressure loss, and crossflow effect within a channel of inline impinging jets. The jet diameter is 5.08 mm and the jet-to-jet spacing in the streamwise and spanwise directions is fixed at x/d = 11.1 and y/d = 5.9, respectively. The effect of jet-to-target surface spacing was considered with z/d = 3 and 6. For both of the jet-to-target surface spacings, a smooth surface, the reference case, and a surface roughened with partial height pins were investigated. The roughened surface has a staggered array of 120 partial height copper pin fins. The pin to jet diameter and the pin height to diameter ratios are D/d = 0.94 and H/D = 1.6, respectively. Regionally averaged heat transfer coefficient distributions were measured on the target surface, and these distributions were coupled with pressure measurements through the array. The heat transfer augmentation and pressure penalty were investigated over a range of jet Reynolds numbers (10K–70K). The results show high discharge coefficients for all the cases. The channels with the tight jet-to-target surface spacing experience double the cross-flow effect of its increased spacing counterpart. The addition of surface roughness showed a negligible effect on the crossflow. The best heat transfer performance was observed in the impingement channel with the pinned target surface at z/d = 3.

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