Jiaming Xu

In response to the severe wear of centrifugal pumps, Workbench workflow is utilized to adjust the blade inlet and outlet angles, aiming to reduce the wear of the impeller and volute of the centrifugal pump and optimize the pump’s efficiency and head. Orthogonal experiments are conducted by varying the inlet and outlet angles. The original sample points are expanded and optimized in combination with the support vector machine and grid search. The optimization results indicate that under the condition of spherical particles, the efficiency at the rated operating condition increases by 1.71%, and the head rises by 0.35%. The appropriate eddy currents formed by increasing the impeller inlet angle alleviate the particle deposition phenomenon in the centrifugal pump, resulting in a smoother particle flow. The wear of the centrifugal pump blades decreases from 40.76 × 10⁻⁷ mm to 7.77 × 10⁻⁷ mm. After optimization, the overall entropy generation rate of the volute decreases, while that of the blade suction surface and the impeller outlet area increases. Additionally, through empirical mode decomposition analysis, it is found that the optimized design reduces high–frequency interference and the pulsation amplitude, making the flow field more stable. The frequency distribution also shifts from being dominated by high–frequency components to concentrating energy in the medium- and low-frequency regions.

The centrifugal pump is an important component of pumped storage power stations, but the axial force on the impeller significantly affects their stability. Hence, this study focuses on the IS80-65-160 centrifugal pump model and employs Dynamic Mode Decomposition (DMD) to analyze the flow field decomposition of the impeller’s axial forces at three operating points: 1.0nr–1.0Qr, 1.0nr–0.4Qr, and 0.4nr–0.4Qr. The results indicate that DMD can decouple the axial forces on the impeller and extract the temporal mono-frequency coherent structure features and their changes corresponding to the main modes of axial forces, with a nearly zero decay rate and stable periodic vibrations. The first four modes of axial force account for 99.7% of the total modal energy, with the average flow field (mode 0) containing the most flow energy and having the greatest impact on the flow field, The impeller vibrations caused by axial forces mainly occur at the impeller outlet. Modes 1 to 4 of the flow field exhibit similar periodic anti-symmetric coherent structures. At the design speed, the flow field structure is dominated by shaft frequency, but this influence significantly decreases when the speed deviates from the design speed. The findings of this study can help enhance centrifugal pump stability.