ارزیابی سه‌بعدی هندسه مولد گردابه طولی در مبدل پره–لوله برای ارتقای انتقال حرارت با کاربرد در مهندسی پزشکی

This study numerically evaluates, in three dimensions, the thermo-hydraulic performance of a fin-and-tube heat exchanger equipped with longitudinal vortex generators (LVGs). The objective is to quantify how vane shape enhances heat transfer while balancing the accompanying pressure drop, with emphasis on biomedical uses such as blood warmers and heat exchangers in life-support systems. Two LVG shapes—triangular and semi-cylindrical—were modeled and simulated under conditions spanning near-wall laminar up to transitional flow. The results show that the semi-cylindrical vane generates more persistent longitudinal vortices, promotes stronger near-wall mixing, thins the thermal boundary layer, and increases the average convective heat transfer relative to the triangular vane, albeit with a higher pressure drop. As the Reynolds number rises, heat transfer is strengthened and pressure loss increases; conversely, raising the inlet temperature of the cold stream reduces the wall heat-transfer coefficient. Within the operating range examined, the semi-cylindrical vane offers a more favorable heat-transfer/ pumping-power trade-off for compact biomedical heat exchangers.