Semi-open type impeller for controlling clearance leakage of centrifugal pump

The invention discloses a semi-open type impeller for controlling clearance leakage of a centrifugal pump. The semi-open type impeller is positioned between a pump shell and a pump cover and comprises a rear cover plate (1), blades (2), surface textures (4), groove parts (5), an inlet pipe (9), a pressure surface (21) and a suction surface (22); and the semi-open type impeller is characterized in that the blade tops of the blades comprise the groove parts (5), first blade tops (23) and second blade tops (24), the first blade tops and the second blade tops are located on the two sides of the groove parts respectively, the first blade tops and/or the second blade tops are provided with the surface textures (4), the surface textures are each of a bionic microstructure, the bionic microstructures comprise crescent-shaped micro-protrusion textures, and the crescent-shaped micro-protrusion textures are regularly arranged on the surface of the blade tops according to a rectangular array. The impeller structure has t