一体化泵站自清洁流动特性研究及优化

Optimizing and Self-Cleaning the Prefabricated Pumping Station Based on Two-phase Fluid Modelling

【目的】研究不同底部结构形式对一体化泵站内泥沙淤积的影响。【方法】基于多相流计算理论采用CFX软件对一体化泵站内流动特性进行固液两相流数值模拟。根据一体化泵站底部流场结构特点,设计了平底底部、锥形底部、台形底部和椭圆形底部等4种底部结构形式,计算结果得到试验的验证。【结果】采用平底底部(方案一)和椭圆形底部(方案四)的一体化泵站内存在明显的泥沙淤积,采用锥形底部(方案二)和台形底部(方案三)一体化泵站内未见明显泥沙淤积。在设计流量工况下方案一至方案四中叶轮进口的流速均匀度分别为86.5%、90.7%、94.3%和88.3%。【结论】方案三中台形底部结构一体化泵站泥沙淤积最少,综合性能最高,底部几何结构最合适,能实现一体化泵站的自清洁。

【Objective】Prefabricated pump is commonly used in hydraulic projects and the purpose of this paper is to investigate the influence of the geometrical structure of its bottom on operating performance and sediment deposition in the pump.【Method】The study was based on multiphase flow,in which the solid-liquid interaction within the pump was numerically simulated using the software CFX.Different optimization schemes were designed to realize self-cleaning of the prefabricated pump.Based on the simulated flow field at the bottom of the pump,we compared the performance of four geometric structures:flat bottom,platform bottom,conical bottom and elliptical bottom.【Result】Sediment did deposit in the pump with the flat or oval bottom,but replacing the bottom to cone and bench shape can substantially reduce the sediment deposition.We also found alternative ways to reduce the sediment deposition in the pump.Under the designed flow rate,the fluid velocity uniformity at the inlet for flat,platform conical and elliptical bottom was 86.5%,90.7%,94.3% and 88.3% respectively.【Conclusion】Optimizing the inlet geometry of the prefabricated pump can smoothen flow velocity and reduce siltation.In addition to maintaining high operation efficiency of the pump,it also reduced silt deposition and self-cleaning the pump.Our results have important implications for the design of prefabricated pumping stations in hydraulic projects.