Analysis of Sediment Erosion in a Francis Turbine Vanes Affected by Particle Size

Abstract The Francis turbines are widely utilized for their broad operating head range and high efficiency. Sediment erosion is one of the main reasons for the failure of hydraulic components of Francis turbines. Especially on sediment season, the sediment concentration will increase greatly, and the sand carrying multi-phase flow process on the turbine is complicated, so the erosion problem will be more serious. In this paper, a numerical study was conducted with different sediment particle sizes for a Francis turbine in the Zagunao River Basin station. A simulation of water-sediment two-phase flow through the turbine was conducted using the Eulerian-Eulerian approach. The sediment erosion rates were calculated by using the Tulsa Erosion Model, and the results were comparatively analysed with the hydraulic components erosion pictures to evaluate the performance and the impact of four typical sediment particle sizes. The influence of sediment size on the erosion of Francis turbine stay vane and guide vane is also analysed in detail. The study elucidates the mechanisms of sediment-induced damage to these components, and significant engineering insights may be provided for weakening a Francis turbine erosion.