Measured and Predicted Flow Near the Exit of a Radial-Flow Impeller

Abstract

Experimental measurements are presented of the velocity field near the exit of a radial impeller with backward-curved blades. The flow pattern, and its variation with changes in the flow coefficient, are compared with numerical predictions on a blade-to-blade plane. The theoretical flow prediction method assumes inviscid flow, is essentially two-dimensional and is based on the streamline curvature approach. It does not specifically require the condition of zero absolute vorticity. The comparison with experiment indicates that the principal feature of the flow not accounted for in the inviscid model is the region of low velocity near mid-blade height on the suction surface, especially for higher blade loadings.