那苏瓦卡里水电站沉沙池沉沙及冲沙效果研究

Study on sand depositing and sand flushing effect in grit chamber of Rasuwagadhi Hydropower Station

在水利水电工程中一般都采用沉沙池来降低泥沙含量,减小泥沙对引水发电系统产生的不利影响,沉沙池中含沙水流流态及沉沙冲沙效果的研究就显得极为重要。基于尼泊尔那苏瓦卡里水电工程的沉沙池,采用理论公式、RNG k~ε紊流模型及体积分辨率函数VOF模拟计算了沉沙池内水沙两相流的水流形态,并详细展示了多组分泥沙颗粒组合中不同颗粒直径泥沙的沉积效果。结果表明:不小于0.2 mm粒径的泥沙沉沙率达到95%以上,数值计算结果与采用理论公式计算得出的沉沙率保持较高的吻合性,满足工程设计要求。

In water conservancy and hydropower projects,a grit chamber is generally used to reduce the sediment content,so as to reduce the adverse impact of the sediment on the water diversion and power generation system.It is very important to study the flow pattern of sand-containing water flow,sand depositing and sand flushing effect in the sand grit chamber.Based on a grit chamber of Rasuwagadhi Hydropower Station,using the theoretical formula,RNG k~εturbulence model and volume resolution function VOF,we simulated the flow pattern of the two-phase flow of sediment in the grit chamber,and showed the deposition effect of different sand particle in the multi-diameter particle composition in detail.The results showed that the sand depositing efficiency of no less than 0.2 mm was more than 95%,and the numerical results agreed with the theoretical calculation and met the engineering design requirements.