HEAT-TRANSFER ENHANCEMENT IN A SERPENTINE CHANNEL

Forced-convection heat transfer rates and pressure drops were measured in the thermally fully developed region of a serpentine channel over Reynolds numbers ranging from 250 to 10000. The wall geometry was similar to # 17.8-3/8W of Kays and London [Compact Heat Exchangers (3rd Edn). p. 204. McGraw-Hill, New York (1984)], but carefully designed to minimize the extent of flow separation. The spatially-periodic wall impingement currents and high shear stresses combined to make a more uniform streamwise variation in local heat flux compared with corrugated surfaces. On an equal-Re basis. the heated surface of the serpentine channel outperformed the baseline parallel-plate channel by about a factor of 9 in air and 14 in water. Thus wavy-walled channels may prove effective for enhancing heat transfer in laminar and transitional flow regimes.