NUMERICAL INVESTIGATION OF FLOW AND HEAT TRANSFER CHARACTERISTICS IN A HAIRPIN HEAT EXCHANGER

To investigate the influence of baffle structure on the flow and heat transfer characteristics of hairpin heat exchangers, this study designs a series of baffle configurations with varying geometries. Numerical simulations are conducted to analyze the thermal-hydraulic performance of the heat exchanger under different baffle counts and notch heights. Empirical correlations are employed to calculate the heat transfer coefficients, thereby validating the simulation results. The results demonstrate that both the baffle count and notch height significantly affect the heat transfer coefficient. Specifically, the baffle count determines the notch position in the elbow section, with the inner-elbow notch configuration showing a pronounced enhancement in heat transfer efficiency. Additionally, the heat transfer coefficient exhibits a nonlinear variation with increasing notch height, and this trend is further modulated by the number of baffles. The comprehensive performance index (J) is observed to improve with larger notch heights. However, its dependence on baffle count follows a nonmonotonic trend, initially increasing before declining beyond an optimal number. This study systematically summarizes the effects of key baffle parameters on hairpin heat exchanger performance, providing actionable insights for their optimized design.