Enhancement of jet-to-wall heat transfer using axisymmetric grooved impinging plates

An experimental investigation was carried out to examine the effects of axisymmetric lathe-worked grooves on the impinging jet-to-wall heat transfer, under constant wall temperature conditions. This study covers jet Reynolds numbers, based on the orifice diameter D, from 15 000 to 30 000, for a given jet-to-wall dimensionless distance H/D = 2. The grooves have either square or triangular cross-section, with depth c = 1 mm, and pitch p = 2 mm. Under these conditions, we obtained significant heat transfer enhancements, up to 81% as compared with the smooth plate reference case, for a value of the dimensionless plate radius R/D = 2, a jet Reynolds number Rej = 23 000, and for square cross-section lathe-worked grooves.