Study on the effect of layered staggered impellers on low-frequency excitation characteristics of centrifugal pumps

Vibration and noise issues in centrifugal pumps, arising from low-frequency excitation, present significant challenges to pump performance and operational stability. To address this, a layered staggered impeller structure is proposed. The conventional six-blade impeller is divided into front and rear layers with three staggered angles: 15°, 30°, and 45° (defined as St15, St30 and St45). Based on Delayed Detached Eddy Simulation (DDES), the effects on hydraulic performance and pressure pulsation characteristics are analyzed. The results demonstrate that the uniformly staggered configuration (St30) achieves optimal performance, yielding a 6.99% efficiency improvement over the original impeller under design conditions. For low-frequency excitation suppression, hydraulic excitations induced by rotor-stator interaction are effectively reduced by St30. Under design conditions, blade passing frequency energy is decreased by 87.26%, double blade passing frequency energy is reduced by 11.51%, and overall pressure pulsation energy in the volute within 10-1k Hz range is decreased by 52.49%. It is revealed by jet wake quantitative analysis that improved uniformity of pressure and velocity distribution is achieved at the impeller outlet after uniform blade staggering, with the standard deviation σ of outlet flow surface velocity being reduced by 27.1%. Phase-locked pulsation energy between front and rear blade layers is effectively reduced by utilizing temporal phase differences in rotor-stator interaction signals. Layered staggered impellers can be considered as an effective technical approach for low-noise centrifugal pump design.