基于CCHE模型的重力沉沙池水沙数值模拟

为了研究重力沉沙池流量、含沙量与水沙分离效率的关系,借助CCHE软件,建立CCHE2D水沙两相流数学模型,采用混合掺长紊流模型,对重力沉沙池进行数值模拟,得到沉沙池内水流流态、悬移质输移规律以及沉沙池的水沙分离效率,并在前人研究的基础上,进一步对不同流量、含沙量情况下,其流量和含沙量对沉沙池水沙分离效率的影响进行分析。结果表明:当流量在0. 05～0. 30 m~3/s时,随着流量增大,则流速增大,水流挟沙力增大,不利于泥沙沉降,使沉沙池的水沙分离效率降低;改变初始含沙量(5～20 kg/m~3),随着初始含沙量的增大,由于沉淀池尾部回流区存在,使得部分泥沙直接被带入清水池,使得沉沙池水沙分离效率降低。

Numerical simulation of water and sediment in gravity settling basin based on CCHE model

In order to study the relationship between the flow and sediment concentration of the gravity settling basin and the water-sediment separation efficiency, this paper sets up a CCHE2D mathematical model for water sediment two phase flows with the aid of CCHE software and uses the mixed length turbulence model to numerically simulate the gravity settling basin so as to get the flow state of the settling basin, the transport law of suspended load and the water-sediment separation efficiency of the settling basin. In addition, based on the previous studies, this paper further analyzed the influence of flow and sediment concentration on water-sediment separation efficiency of the settling basin when flow and sediment concentration are different. The results showed that when the water flow is from 0.05 to 0.3 m³/s, as the flow increases, the flow rate quickens, and the sediment carrying capacity increases, which is not conducive to sediment deposition and will reduce the water-sediment separation efficiency of the settling basin and change the initial sediment content (5 to 20 kg/m³). As the initial sediment content increases, some sediments will be directly brought into the clean water basin because of the existence of tail reflux area of the sediment basin, which will reduce water-sediment separation efficiency of the settling basin.