OPTIMUM HYDRAULIC DESIGN FOR A RADIAL DIFFUSER PUMP USING ORTHOGONAL EXPERIMENTAL METHOD BASED ON CFD

摘要

To improve the performance of the centrifugal pump with a vaned diffuser, the influence of impeller geometric parameters on external characteristics of the pump was investigated by Orthogonal Experimental Method (OEM) based on CFD. Blade outlet width b_2, blade wrap angle Φ, blade outlet angle β_2, and blade number Z were selected as the main impeller geometric parameters and the orthogonal experiment of L_9 (3~3*2~1), which contained 3 levels of the 3 factors and 2 levels of one factor, was done in this study. Three-dimensional steady simulations were conducted by solving the RANS equations in the design procedure with SST k-ω turbulence model, and about 5.3 million structured grids for the whole calculation domains were used. The experimental results were justified by the variance analysis method. The inner flow of the pump was also analyzed in order to obtain the flow behaviors that can affect the pump performance. The results showed that the blade outlet angle β_2 had the greatest influence on the efficiency and power. The high efficiency area of the optimal impeller is wider. The final optimized impeller accomplished better pump performance, which meet the design requirements. The velocity distribution in the optimized impeller is more regular and the area of the high turbulence kinetic energy is smaller in the optimal impeller.