Effect of using multiple vortex generator rows on heat transfer enhancement inside an asymmetrically heated rectangular channel

Enhancing the convective heat transfer is essential in solar applications for efficiency improvement. This can be achieved using Vortex Generators (VGs). Previous studies have focused on distinguishing the best VGs design while considering single VGs row configuration. In this paper, a study is conducted on investigating the effect of using multiple VGs rows configuration with varying longitudinal pitch (LP) separating the rows at Reynolds number Re = 2000. Then, the effect of increasing the air flow rate is studied by varying Re in the range of 2000-10,000. The SST k-omega model is chosen to model the turbulence at high Re. Validation is performed by comparing the numerical results to numerical and experimental data from the open literature. The best configuration is obtained when using five VGs rows with LP = 3H which increases the thermal enhancement factor by 69 % and 90 % with respect to empty channel configuration at Re = 2000 and 10,000 respectively. Then, local analyses are performed to better understand the physics behind the heat transfer enhancement in the best configuration. Finally, Nusselt number and friction factor correlations are developed to be representative of a dynamic model of photovoltaic/thermal (PVT) systems with vortex generators.