不同鳃片间距下的分离鳃内部流场三维数值模拟

为研究鳃片间距对分离鳃的速度场及泥沙分布特性的影响,采用Fluent软件中的层流模型和欧拉模型,运用Phase Coupled SIMPLE(PC-SIMPLE)算法,对不同鳃片间距下分离鳃的水沙两相流流场进行了静水沉降的三维数值模拟。根据数值计算结果,对速度场和含沙量分布特性进行了对比与分析。结果表明:不同鳃片间距下,分离鳃内部的速度场分布规律有所不同,鳃片间距越大,速度流场受到来自泥沙通道中的泥沙流与清水通道中的清水流影响就越大;鳃片间距越小,分离鳃的沉淀效果越好。以泥沙平均速度和清水平均速度作为考核指标,同时考虑分离鳃内部的流场特性、水沙分离效果与制作分离鳃的成本,则最佳鳃片间距为5 cm。

3D Numerical Simulation of Internal Flow Field in Gill-piece Separation Device under Different Gill-piece Spacing

To study the effect of gill-piece spacing on velocity field and sediment distribution in gill-piece separation device, 3D numerical simulation based on laminar model, Eulerian model and Phase Coupled SIMPLE algorithm provided by Fluent software was conducted in simulating water-sediment flow field of different gill-piece spacing under hydrostatic condition. The velocity field and the distribution of sediment concentration were compared and analyzed according to the numerical results. It indicated that the velocity distribution was different under different gill-piece spacing. The effect on velocity flow field from sediment flow in the sediment channel and clear water flow in water channel would get greater as the gill-piece spacing became greater. When the gill-piece spacing was smaller, the precipitation effect would be better in gill-piece separation device. Taking the average velocity of sediment and clear water as the examination index and considering the characteristics of flow field, effect of water-sediment separation, and cost of making gill-piece separation device, the best gill-piece spacing was proposed as d=5 cm.