철도차량 냉각송풍기 공력성능 향상을 위한 임펠러 익형 최적설계

초록

In the cooling systems of railway vehicle components such as Variable Voltage Variable Frequency (VVVF) inverters and Static Inverters (SIV), cooling fans are commonly employed. However, under low Reynolds number operating conditions, conventional fan geometries exhibit a significant decrease in efficiency. To address this issue, this study proposes a new airfoil, termed the Low-Reynolds for Easy Manufacturing Airfoil (LoREMA), specifically designed for low Reynolds number regimes. The proposed LoREMA was developed by systematically defining key geometric parameters―maximum thickness, maximum camber, camber position, leading-edge angle, and trailing-edge angle―and determining the optimal combination based on lift-to-drag ratio performance. When applied to the cooling fan impeller blade and analyzed numerically, the LoREMA achieved an efficiency of 67.8% at the same flow rate condition (0.20 m³/ s), representing a 46.9% improvement compared with the conventional Mitsubishi fan. In addition, the required shaft power decreased by 36.5%, demonstrating superior energy efficiency. These results confirm that, even under constrained railway vehicle operating conditions, optimization of the airfoil geometry alone can effectively enhance the efficiency and static pressure performance of cooling fans.

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