Characterization of Thermal and Hydraulic Performance of Fin-and-Tube Heat Exchanger Using Rectangular Winglet Vortex Generator with Punched Hole 2020-01-1346

Vortex generation has been emerged as one of the promising passive technique for improving air-side heat transfer performance of air cooled heat exchangers. It can be achieved by employing small flow turbulators, called vortex generators (VGs), which are installed on the heat transfer surface (fins). VGs can generate longitudinal vortices, which strongly disturb the flow structure, and have a significant influence on the velocity and temperature distributions, causing improved thermal transport. In this study, three dimensional numerical analyses have been carried out to examine the thermo-hydraulic performance of fin-and-tube heat exchangers (FTHE) by using rectangular winglet vortex generator (RWVG) with a circular punched hole. The augmentation in the performance of heat exchanger with RWVG having punched hole is established and compared with baseline case (without VG) by solving the Navier Stokes and energy equations with a Finite Volume Method in body fitted grids. The developed numerical model is validated with the previous published results. RWVGs have been installed in common-flow-down (CFD) configuration on the top surface of fin behind the circular tubes. Further, four different attack angles (i.e., 10°, 20°, 30° and 45°) are tested to establish impact on flow structure, Nusselt number, pressure drop, and j/f factor. The range of Reynolds number have been taken from 400 to 2000. RWVGs with a circular punched hole remarkably improves the thermo-hydraulic performance. Also, reduction in pressure drop penalty and friction factor is observed due to reduction in heat transfer surface area. 10° angle of attack for RWVG with a circular hole found best with 12-30% augmentation of heat transfer and about 3.39-9.24% reduction in pressure drop penalty.