Cylindrical blades with involute contour

Flow separation from blade surfaces caused by high adverse pressure gradient within low specific speed impellers contributes considerably to the low efficiency of the impeller. Authors of this paper showed two important geometrical involute properties of involutes by kinematics theorems, which are expected to control flow separation and improve hydraulic efficiency of impellors. CFD results indicate that involutes are superior to other curves commonly used in hydraulic features. Detailed calculating and drawing process about the involute is presented in the paper to help engineers apply this new type of curve in cylindrical blade design practice.