W-Shaped Rib Pitch Effect on Jet Impingement Heat Transfer in Rectangular Channel

For evaluating the heat transfer performance in a jet impingement cooling system featuring W-shaped rib turbulators, an experimental investigation was completed. Six different configurations, including three W-rib pitches ([Formula: see text], 9, and 6) and two jet-to-target surface spacings ([Formula: see text] and 6), were considered to completely assess their influence on the heat transfer, pressure loss, and crossflow of a relatively long impingement channel with an in-line array of [Formula: see text] impinging jets. Moreover, the regionally averaged heat transfer coefficients were evaluated based on two different reference temperatures: jet inlet temperature and local bulk temperature. Each configuration was experimentally tested at four Reynolds numbers, based on the jet diameter ([Formula: see text]), using the copper plate experimental method. The results show that the heat transfer enhancement can reach up to 25% in the narrow channel with the [Formula: see text] configuration. Also, the crossflow can deteriorate or enhance the local heat transfer along the channel. The discharge coefficients showed minimal variations, and the pressure loss increased in the W-rib channels is between 1.3 and 2.5 times the smooth channel pressure loss. Finally, a design correlation was developed for the area-averaged Nusselt number estimation in W-rib roughened impingement channels.