Study on the Interference between Moving and Stationary Blade Rows in Axial-Flow Blower

Abstract

It is well known that for small axial-distance between moving and stationary blade rows in axial-flow blower, interference arises on the blades, and the force acting on the blades fluctuates. The main causes of this interference are the relative movement of the circulation induced by the blades and the wakes which flow downstream form the moving blades. Many studies have been made concerning this problem, mainly from a theoretical point of view, but experimental studies are few. In this study, we analysed the interference between moving and stationary blade rows in an axial-flow blower. Four variations of a single stage axial-flow blower with the stationary blade row behind the moving blade row and with the same performance were used. The number of moving blades was 3 or 9, and thin aerofoil or NACA 65-Series profile was used for the moving blade. Measurements were made of the fluctuating forces on the stationary blades for various axial-distances between blade rows. Comparisons of the fluctuating forces calculated following the method of Kemp and Sears were made.