Flow visualization of flat and curved trapezoidal winglet vortex generator in fin-and-tube channel in inline arrangement

In this study, a flow visualization experiment using the dye injection technique was conducted. Visual observation of the flow characteristics across the scaled up fin-and-tube heat exchanger (FTHE) channel model with and without trapezoidal winglet vortex generator (TWVG) were presented. Four cases of FTHE channel in inline tube arrangement were examined with TWVG at different geometries and arrangements, as well as a case without the vortex generator. The two TWVG geometries used in this study were a flat trapezoidal winglet (FTW) and a curved trapezoidal winglet (CTW) either arranged in common flow up (CFU) or common flow down (CFD) compositions. The Reynolds number (Re) used ranged from 500 to 2500. It was found that with the introduction of TWVG in the FTHE channel, the wake region size behind tubes reduced compared to the baseline case. However, the formation of an additional wake region behind the TWVG was also observed.