Stokes数对含沙水流中Pelton水斗磨损的影响
Effect of Stokes number on erosion on Pelton buckets for sediment-laden flows
AI总结：
本研究通过数值模拟分析Stokes数对Pelton水斗射流中颗粒分布的影响，发现高Stokes数下分布不对称，且均匀粒径假设会低估斗尖和分水刃磨损，实际分布更准确。
摘要：
随着冰川融化加剧以及为维持生态系统健康而需保持泥沙连续性，水电站中含沙水流的通过日益成为问题，尤其是对转轮叶片和水斗的磨损。一种广泛采用的缓解策略是使用过滤器来保护Pelton水轮机。然而，这些过滤器会导致水库中泥沙快速淤积，必须频繁排水以维持库容。此类排水作业成本高昂，因此要求在保证转轮完整性的前提下延长排水间隔，因为磨损引起的应力集中可能导致水斗破裂。为了更好地理解在不同运行和泥沙条件下转轮磨损的原因，以便让更多泥沙安全通过水力机械，对转轮磨损成因的深入认识至关重要。本研究探讨了通过喷嘴的含沙水流在不同Stokes数下对射流中颗粒分布的影响。此外，还分析了在模拟Pelton水轮水斗磨损时，实际颗粒粒径和空间分布与假设颗粒均匀分布且粒径为平均值的差异。结果表明，在低Stokes数下，射流中的颗粒分布呈相似的轴对称形状，而在较高Stokes数下则变为不对称。此外，研究显示，在模拟水斗磨损时，假设颗粒均匀分布且粒径为平均值会低估斗尖和分水刃的磨损，而采用实际粒径和空间分布则能捕捉到这些磨损。
英文摘要：
With increased glacial melting and the need to maintain sediment continuity for ecosystem health, sediment-laden flows through hydropower plants are becoming increasingly problematic, particularly due to erosion on runner blades and buckets. A widely used mitigation strategy is the use of filters to protect Pelton turbines. However, these filters lead to rapid sediment accumulation in reservoirs, which must be drained frequently to maintain storage capacity. The high cost of such drainage operations calls for longer intervals between them, without compromising runner integrity, as erosion-induced stress concentrations may cause bucket rupture. A better understanding of the causes of runner erosion under varying operational and sediment conditions is essential to allow more sediment to pass through the hydraulic machine safely. This study investigates how sediment-laden flow through the nozzle affects particle distribution in the jet for different Stokes numbers. Furthermore, it analyses how a realistic particle size and spatial distribution in the impacting jet compares to the assumption of a uniform particle distribution with particles of mean size when simulating bucket erosion in Pelton wheels. The results show that the particle distribution in the jet follows a similar axisymmetric shape for low Stokes numbers whereas at higher Stokes numbers it becomes asymmetric. Additionally, it is shown that imposing uniform particle distribution with particles of mean diameter under-predicts tip- and splitter erosion when simulating the erosion on the bucket but is captured by imposing the realistic size and spatial distribution.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
