Abstract: The Yellow River carries huge amount of suspended particles, which would cause sediment erosion on flowing components of hydraulic turbines. The selection of a proper erosion model is crucial for the accurate numerical prediction of the erosion depth. In this study, four erosion models are applied respectively to numerically simulate the solid-liquid two-phase flow in a right-angle bend under the conditions of two particle diameters and two flow velocities. By comparing the predicted erosion depth with previous experimental data in literature, we screen out suitable erosion models for the numerical simulation of erosion caused by suspended sediments from the Yellow River. The results show the erosion zones are concentrated on the connecting sections of the upstream and downstream turbine pipelines and the downstream circumferential locations of 90°and 270°, and erosion caused by large particles can also be observed in the range of 90° - 270°. In general, both the Tusla model and Oka model could perform better accuracy. The Oka model is recommend for simulations with larger sediment particles, which is equipped with the factor of sediment particle diameter and is superior in accuracy. The Tusla model, yielding the highest accuracy, has better performance in small sediment particle conditions. Oriented to the hydropower stations in the Yellow River basin, this study suggests the selection of proper numerical model for sediment erosion simulation.

Key words: solid-liquid two-phase flow, erosion model, relative erosion depth, suspended load, particle impact velocity, particle impact angle