Influence of crossflow-induced swirl and impingement on heat transfer in atwo-pass channel connected by two rows of holes

Detailed heat transfer distributions are presented inside a two-pass coolan t square channel: connected by two rows of holes on the divider walls. The enhanced cooling is achieved by a combination of impingement and crossflow v-induced swirl. Three configurations ar e examined where the crossflow is generated from one coolant passage to the adjoining coolant passage through a sei ies of straight straight and angled holes and a two-dimensional slot placed along the dividing wall. The holes/slots deliver the flow front one passage to another. This is typically achieved in a conventional design by a 180 deg U-bend Heat transfer distributions will be presented on the side walls of the passages. A transient liquid crystal technique is applied to m easure the detailed heat transfer coefficient distributions inside the pass ages. Results for the three-hole supply cases are compared with the results SI om the traditional 180 deg tom passage for three channel Slow Reynolds numbers ranging between 10,000 and 50,000. Results show that the new Seed s ystem, from first pass to second pass using crossflow injection holes, prod uces significantly higher Nusselt numbers on the second pass walls. The hea t transfer enhancements in the second pass of these channels are as much as two to three times greater than that obtained in the second pass for a cha nnel with a 180 deg turn. Results are also compared with channels that have only one row of discharge holes.