Flow loss and structure of circular arc blades with different leading edges

Abstract

Due to much lower cost of development and production, circular arc blades are often applied to axial flow fans. However, compared with NACA 65 profile, circular arc blades have higher losses, which are caused by the formation of separation bubbles or complete separation at the leading edge. Therefore, it is necessary to identify a specific geometry of leading edge, which can reduce the separation bubbles or complete separation. In this article, circular arc blades with different leading edges are examined by numerical method. The numerical investigations were performed with Reynolds numbers of [Formula: see text] and [Formula: see text]. All examinations were performed for different incidence angles. The influence of the sidewall on the flow loss and behavior is taken into account. In this article, the influence of leading edge geometry and Reynolds number on the flow losses is shown. The occurrence of flow behavior such as separation bubbles at the leading edge, secondary flow, and corner stall is shown and discussed. The flow structure on the blade and the corresponding sidewall region is illustrated with numerical streamline figures.