Optimization Design of Centrifugal Pump Auxiliary Blades Based on Orthogonal Experiment and Grey Correlation Analysis

In order to improve the hydraulic performance of multistage centrifugal pumps through the utilization of auxiliary blades, this paper presents an optimization of these blades using orthogonal experiments and grey relational analysis. The optimization scheme for auxiliary blade structure resulted as follows: Z = 2, R = 46.9 mm, and W = 2.5. In the vicinity of the optimal operating point, the optimized scheme showed a 6% increase in head compared to the original scheme. The increase in head was not significant at low flow rates, but at high flow rates, the optimized scheme exhibited a substantial increase in head, approximately 23% higher than the original scheme. Using the L-9(3(4)) orthogonal array, the quantity (Z), inner diameter (R), and width (W) of the auxiliary blades were selected as factors, each with three levels, to design nine different impeller structures. An entire flow field numerical simulation of a five-stage centrifugal pump was conducted for the nine designs, obtaining the pump head under rated working conditions. Based on the range analysis method of orthogonal experiment, the optimal design scheme for pump head performance was derived, and the primary and secondary factors affecting the pump head were found to be the inner diameter (R), width (W), and quantity (Z) of the auxiliary blades. The accuracy of the orthogonal experimental results may have been influenced by the different factor level dimensions, and a grey relational analysis was conducted to verify the accuracy of the results, on top of the range analysis of the orthogonal experiment. A prototype was created according to the optimal solution, which under optimal conditions presented a total pump efficiency of 32.6% and a pump head of 41.39 m, significantly higher than the original design without auxiliary blades. This combination of numerical simulation with orthogonal experiments and grey relational analysis is suitable for the optimization design of auxiliary blades in multistage centrifugal pumps. This approach can accurately infer the effect of the primary and secondary factors of the geometric parameters of auxiliary blades on pump performance and their corresponding optimal solutions.