The vortex-dominant mechanism behind the characteristic erosion pattern observed in a double-suction centrifugal pump

The operational reliability of double-suction centrifugal pumps in sediment-laden flows is severely compromised by erosive wear, but the underlying fluid dynamic mechanisms that link specific flow structures to characteristic erosion patterns remain uncertain. This study integrates field observation, dynamic erosion experiments, and numerical simulation to elucidate these mechanisms for a typical Yellow River irrigation pump. We reveal that the characteristic erosion patterns are fundamentally governed by vortex-dominated particle transport, specifically by the flow-controlled spatial distribution of the number of impacts. Two interlinked vortex-driven mechanisms are identified. The passage vortex not only drives particles from the pressure side toward the suction-side outlet but also redistributes them on the pressure side into a characteristic hourglass-shaped concentration pattern, explaining severe erosion near the inlet hub region and the downstream tongue-shaped erosion zone of the pressure side. At the suction-side outlet, the passage vortex merges with other secondary flows to form a concentrated vortex core. This core retains part of the incoming particles and induces repeated wall impacts, directly producing the observed triangular erosion zones. These findings provide a direct mechanistic basis for understanding how coherent vortex structures regulate particle transport and localized erosion patterns in sediment-laden rotating flows.