该文对分离鳃内的水沙两相流流场进行了数值模拟，多相流模型分别采用了欧拉模型与混合模型，将两种多相流模型的计算结果与PIV测试结果进行了定性和定量对比，发现欧拉模型比较适合分离鳃内的水沙两相流流场数值模拟。进而利用欧拉模型的计算结果分析了分离鳃内的泥沙及速度分布特性，结果表明，鳃片上表面、下表面的平均含沙量和平均速度分布规律与鳃片所在位置和时间有关，分离鳃不同高度方向的泥沙分布特性不同，越靠近分离鳃的上端，其水沙分离速度越快，就越容易获得清水；泥沙通道中泥沙平均速度与清水通道中清水平均速度随时间变化规律一致，且泥沙平均速度总体上大于清水平均速度。%Gill-piece separation device, which consists of gill-pieces and gill-duct, is a kind of new-type device with advantages of simple structure, low cost and fast water-sediment separation velocity. This device is found wide applications in sediment pretreatment at water works or the treatment of irrigation water. With the development of computer technology and computational fluid dynamics, solid-liquid two-phase flow field simulated by numerical model have been widely used. This paper adopts multiphase flow model that is Eulerian model and Mixture model provided by Fluent software to study water-sediment two-phase flow field in the gill-piece separation device under hydrostatic condition. At the same time, in order to check the reliability of numerical simulation, the test data of PIV technique are used to evaluate the simulation results. This paper shows velocity vector distribution and velocity nephogram of part of the sections using Eulerian model, mixture model and PIV test results under the condition of S=10kg/m³. It is shown that velocity vector distribution obtained by Eulerian simulation and Mixture simulation are the same as those from the PIV test. The flow is dominated by sediment flow settlement in the section of Z=0.035m along width direction and the section of X=0.005m along length direction. The sediment particles slide downward along the short sides of the gill-pieces at an inclination angle ofα. When they reach the long side of the gill-pieces, they surge to sediment channel along with particles at inclination angle of β. The flow is dominated by upward movement of clear water in the section of Z=0.005m along width direction and the section of X=0.095m along length direction. The clear water flow upward along the short side of gill-piece at inclination angle ofα. When they reach the long side of the gill-piece, they move upward to enter the water channel at an inclination angle ofβ. But velocity nephogram of different sections is different between simulation results and PIV test results at the same time point. The maximum relative errors of calculation results by Eulerian model and Mixture model from PIV test result are 9.09% and 36.36%, respectively. So Eulerian model is more accurate and reliable, and is used to simulate water-sediment two-phase flow in the gill-piece separation device. And than the distribution characteristics of sediment and velocity in gill-piece separation device is analyzed using Eulerian model calculation results. Average sediment concentration and velocity distribution, which is on the upper surface and the lower surface of the gill-piece, is relevant with gill-piece location and time. The characteristic of sediment distribution is different along different height direction of the gill-piece separation device. The faster water-sediment separation is, when closer to top of gill-piece separation device, the easier it is to get water. The variation of average sediment velocity with time in sediment channel is consistent with average water velocity in the water channel. And average sediment velocity is generally larger than average water velocity.
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