Numerical simulation and optimization of hyperbolic dimpled louvered fin heat exchanger

Abstract

Louvered fin heat exchangers are widely used in automotive air conditioning systems owing to their compact structure and excellent heat transfer performance. To further improve their thermal-hydraulic performance, this study proposes a novel hyperbolic dimpled louvered fin. Numerical simulations were performed to compare the flow and heat transfer characteristics of the hyperbolic dimpled louvered fin with those of the conventional louvered fin over a Reynolds number range of 100-500. In addition, the structural parameters were optimized using response surface methodology. The results show that the dimpled structure enhances local flow disturbance, induces vortex formation, and improves convective heat transfer. The optimal parameter combination was determined as an aspect ratio of k = 4.3, a louver angle of θ = 29.4°, and a fin pitch of Lp = 2.08 mm. Among these parameters, the louver angle had the greatest influence on the comprehensive performance factor, and a significant interaction was observed between the louver angle and the aspect ratio. Under the optimized conditions, the hyperbolic dimpled louvered fin exhibited better overall performance than the conventional louvered fin. Compared with the conventional louvered fin, the heat transfer factor j increased by 2.3%-4.4%, the friction factor f increased by 2.5%-3.1%, and the comprehensive performance factor JF increased by 2.1%-3.5%. These results indicate that the proposed fin structure can enhance heat transfer while causing only a limited increase in flow resistance, providing useful guidance for the design of high-performance louvered fin heat exchangers.