Optimization of cavitation performance and hydraulic performance of multistage pump based on response surface method

The structural parameters of the first stage impeller have an important influence on the performance of multistage pumps, and the purpose of our study is to find the most significant factors affecting the performance of double-casing multistage pumps, and then to carry out a comprehensive optimization of the hydraulic performance and cavitation performance. With the Plackett-Burman design method, we made a notability analysis on impeller parameters, and the three control variables that are most sensitive to performance of multistage pumps were found. Based on the response surface method, we carried out the central composite design experiments for the sensitive control variables, and established the multiple regression model between the sensitive parameters and the performance parameters. By solving the regression model, the most significant parameters affecting the performance were obtained: impeller outlet angle, outlet diameter and wrap angle. After analyzing the interaction between impeller parameters, it was found that the optimal hydraulic performance and the optimal NPSHr will constrain each other, and the optimal parameter combination with the lowest NPSHr and the hydraulic performance not lower than that of original model is impeller outlet diameter, D21 = 292 mm, the impeller outlet angle, β21 = 19°, and the wrap angle, φ1 = 160°.