梭锥管混浊流体分离装置水沙两相流数值模拟

Numerical simulation of the water-sediment two phase in turbid fluid separation device of shuttle-conical tube

为了探明梭锥管内水沙分离的机理,在不同网格划分方案下,该文对梭锥管内的水沙两相流进行了静水沉降的数值模拟,并将计算结果与实测值进行了对比,选出了最优网格划分方案。在最优网格方案下,采用层流方程和简化的多相流Mixture模型,对梭锥管内部流场进行计算。计算结果表明:在锥圈上表面形成了"泥沙"流下沉,下表面"清水"流上升的小循环运动;作为泥沙沉降的重要边界,锥圈改变了泥沙的沉降方向,缩短了沉降距离,提高了水沙的分离效率;装置内存在水沙绕相邻锥圈形成的小循环流动和沿梭锥管边壁的清水流通道及中心的泥沙流通道做大循环的水沙流现象;两侧通道与锥圈上、下表面流速较大,其余区域流速较小。计算结果与试验结果基本一致,表明层流方程和Mixture模型耦合可以较好地模拟梭锥管内水沙两相流。

In order to understand the mechanism of water-sediment separating in Shuttle-conical tube, the numerical simulation of static water settlement was conducted for water-sediment two phase under the different grid division scheme. Then the calculated results were compared with the experimental data, the optimized scheme was selected at last. The flow field of Shuttle-conical tube was calculated by using laminar equation and simplified mixture model under the selected grid division scheme. It is shown that ＂sediment＂ flow is on the upper surface of conical circles and ＂water＂ flow is on the lower surface of conical circles. The conical circles change the direction of sediment settlement and reduce the settlement distance. Therefore the separation efficiency of water-sediment is improved. There are phenomena that are water-sediment around the adjacent Shuttle-conical tube forming a small circulation and along the Shuttle-conical side wall of water circulation way and center sediment circulation way doing systemic circulation of water -sediment flow in shuttle-conical tube. The velocities are larger which are in the surface of conical circles and in double-side passages of Shuttle-conical tube. But the velocities are very small in other area. The calculated results and test results are basically consistent, which shows the laminar model and Mixture model coupling can be used to simulate the water-sediment two-phase flow in Shuttle-conical tube.