Assessment of particle parameters effects on the wear behavior of hydraulic turbine materials: Insight from CFD–DEM coupling

Hydraulic turbines operating in sediment-laden flows are highly susceptible to erosive wear, which degrades safety, efficiency, and service life. However, most existing prediction methods evaluate wear rates on fixed boundaries and cannot capture the progressive evolution of wear morphology. To address this limitation, a computational fluid dynamics–discrete element method (CFD–DEM) model with dynamic wear-boundary updating is developed and experimentally validated for sediment-laden jet impingement erosion of turbine substrate materials. Numerical results agree well with experimental wear-depth distributions and wear profiles. The effects of particle concentration, size, and shape on wear evolution are systematically investigated. Under vertical jet impingement, wall wear depth exhibits a stable M-shaped radial distribution governed by jet–wall interaction and stagnation-region flow structures. Particle parameters do not alter this basic pattern, but significantly affect the location, magnitude, and extent of wear peaks. Within the investigated range, cumulative volume loss increases approximately linearly with particle concentration, whereas particle size shows a stronger nonlinear effect. At 20 min, cumulative volume loss follows a quadratic relationship with particle size, with a second-order coefficient of 0.00441. Increasing particle size from 25% to 50% relative to the baseline increases cumulative volume loss by about 8.4 mm3, while a 100% increase yields about 85.1 mm3. Sensitivity analysis indicates that particle sphericity has the greatest influence on cumulative volume loss, followed by particle size and particle concentration.