Biomimetic Volute Tongue Design for Combined Hydraulic and Acoustic Optimization in Centrifugal Pumps

To simultaneously reduce flow-induced noise and enhance hydraulic performance in centrifugal pumps, this study proposes a bionic volute tongue inspired by the serrated trailing-edge morphology of the long-eared owl wing. Hydraulic performance and volute-induced noise are integrated into a unified evaluation framework, enabling multi-objective optimization of the tongue geometry. An orthogonal experimental design coupled with Computational Fluid Dynamics (CFD) and Computational Fluid Acoustics (CFA) is employed to systematically assess the influence of serration parameters. A matrix-based decision method is then used to identify the optimal configuration balancing efficiency, head, and acoustic performance. The optimized design reduces the area fraction of extremely high-velocity regions (>18 m/s) from 15.21% to 5.38%, corresponding to a 64.63% decrease, while the flow non-uniformity coefficient ζ is reduced by 26.1%. Under rated operating conditions, the pump head increases by 0.5 m, hydraulic efficiency improves by 5%, and volute-induced noise is reduced by approximately 5 dB. Flow-field analysis indicates that volute-induced noise is the dominant source of hydrodynamic noise, and that the serrated bionic tongue effectively suppresses its intensity. The noise reduction mechanism is attributed to improved rotor-stator interaction, decomposition of large-scale vortical structures, and delayed flow separation, which collectively reduce pressure pulsation at the rotor-stator interface.