Influence of blade leading edge shape on hydraulic and suction performance of a mixed-flow pump

Abstract

The shape of the blade leading edge (LE) is a design variable that cannot theoretically affect the inlet flow characteristics under the definition of the velocity triangle. However, the LE is the first to encounter the working fluid in terms of streamwise direction. Depending on its shape, not only the local flow characteristics but also the performance can be affected. In this study, a numerical analysis of the hydraulic and suction performance for a mixed-flow pump was performed with different shapes of the blade LE. The blade was prepared with four sets according to the ellipse ratio (ER), including a square (ER=0), round (1), elliptic (2), and parabolic (5) shape. As the shape of the blade LE was square, the flow streamline was immediately separated from the blade surface, showing a significant drop in the hydraulic performance. As the blade LE was designed in a round, elliptic, or parabolic shape instead of a square shape, the hydraulic performance did not show a noticeable difference. On the other hand, in the prediction of suction performance, the square LE obtained the best characteristics. As the LE shape gradually became a parabolic shape, the cavity blockage was reduced, and the suction performance was also improved.