Synergistic mechanism cavitation and erosion of the bucket in a Pelton turbine

Abstract During the operation of high-head power stations in flood season, the Pelton turbine is prone to the simultaneous occurrence of cavitation and erosion, which seriously threatens the safe and stable operation of hydropower units. To clarify the synergism between cavitation and erosion of key flow parts of the Pelton turbine, based on the Schnerr-Sauer cavitation model and Oka erosion model, and combined with the motion trajectory of sediment particles, this paper studies the influence of sediment particle parameters on the cavitation and erosion characteristics of bucket. The results indicate that under cavitation effects, with the increase in particle size, the impact erosion on the bucket where the splitter tip divides water gradually intensifies, while the average erosion rate of other buckets shows an overall trend of first increasing and then decreasing. Moreover, the erosion rates of different buckets are proportional to changes in particle concentration. Additionally, by comparing the cavitation characteristics of the Pelton turbine under design conditions, it is found that particles with large sizes and low concentrations tend to aggregate near the back of the bucket, thereby inhibiting the formation and development of cavitation structures in these regions.