The Effects of Impeller Vane Roughness and Thickness on the Characteristics of the Mixed-Flow Propeller Pump

Abstract

Effects of the impeller vane roughness and thickness on the flow conditions and hydraulic losses as well as on the overall performances of the mixed-flow propeller pump are presented. The vane roughness has a most harmful influence upon the optimum performances, and also has a marked effect on the peripheral component of the discharge velocity near the impeller tip. The change in hydraulic losses in the impeller due to the variation of vane roughness is equivalent to that of the flat plate. The effects of roughness at various parts on the vane surface are also discussed. The head-capacity curves with varying vane thickness may be calculated actually on assumption that the capacity varies proportionally to the space area between vanes while the head remains constant.