Experimental investigation of the effect of twisted vortex generators placed in a channel on heat transfer

In this study, the effect of vortex generators, produced in seven different forms using Polylactic Acid (PLA) material via 3D printing, on heat transfer within a rectangular cross-section channel was experimentally investigated. Air was used as the working fluid. Constant heat flux values ranging from 715 W/m² to 1829 W/m² were applied to the bottom surface of the channel, and the Reynolds numbers varied between 2225 and 9448. The effects of twist pitch, hole diameter, and twist direction of the vortex generators with different forms were examined separately in terms of heat transfer. Based on the obtained results, compared to the plain channel, the use of vortex generators resulted in improvements in heat transfer by VJ1 (%9-33), VJ2 (%26-59), VJ3 (%20-51) VJ4 (%32-55), VJ5 (%21-37), VJ6 (%16-45) and VJ7 (%28-78), respectively. It was observed that increasing the twist pitch in the design of vortex generators was effective in reducing surface temperatures. The hole diameters on the surface were found to have no significant effect on heat transfer compared to surfaces without holes. In terms of twist direction, the deflected twist type vortex generator was found to be less effective in reducing surface temperatures than the unidirectional twisted type.