Abstract
The impeller and volute of a single-channel pump used for wastewater treatment were simultaneously optimized to improve the hydraulic efficiency and reduce unsteady radial force sources due to impeller–volute interaction. Steady and unsteady Reynolds-averaged Navier–Stokes equations were solved with the shear stress transport turbulence model as the turbulence closure model using tetrahedral grids to analyze the internal flow in the single-channel pump. Five design variables related to the internal flow cross-sectional areas of the impeller and volute were selected to simultaneously optimize three objective functions: the hydraulic efficiency, the sweep area of the radial force during one revolution, and the distance of the mass center of the sweep area from the origin. A response surface approximation model and a genetic algorithm were employed to obtain the three-dimensional Pareto-optimal solutions representing the trade-off between the efficiency and the radial force sources. The three-objective optimization results showed that the representative clustered optimum designs exhibit enhanced efficiency and reduced radial force sources simultaneously in most cases, compared with the reference design. The trade-off relationship between the efficiency and the radial force sources clarifies with controlling the internal flow cross-sectional areas of the impeller and volute of the single-channel pump. The efficiency improvement and reduction in the radial force sources were systematically verified by analyzing the detailed internal flow characteristics.
