Advancing thermal performance through vortex generators morphing

Abstract

The design of rigid vortex generators (RVG) influences the thermal performance of various technologies. We employed Discrete Adjoint-Based Optimization to show the optimal development of vortex generators. Under turbulent flow conditions, different bi-objective functions on the RVG design were examined. Specifically, we aimed at an optimal RVG shape that minimizes the pressure drop and maximizes the local heat transfer in a rectangular channel. We show that an optimal design of an RVG can be obtained using computational fluid dynamics in conjunction with the Pareto Front at a computational cost of the order ~O(10^{-1}). We obtained three essential vortex generator shapes based on the RVG morphing technique. Compared to the baseline geometry of a delta winglet pair DWP, the first morphed design reduced the pressure drop by 39%, however, at the expense of a 21% reduction in the Nusselt number. The second vortex generator design enhanced the heat transfer by 18%, however, at the cost of a significant increase in pressure drop of about 40%. The final morphed design achieved the highest thermal performance factor of 1.28, representing a heat transfer enhancement of 6% with a moderate increase in pressure drop of about 13% compared to DWP vortex generators. Furthermore, we investigated the effect of introducing different size holes on the mass reduction of vortex generators and their thermal performances. The mass of vortex generators can be reduced by 9% and with an increase of 7% in thermal performance factor concerning the DWP baseline. The findings of this study will lead to highly efficient lightweight heat exchangers.