沉沙池冲沙过程CFD模拟分析

Flushing Process of Sedimentation Basin Simulated by CFD

沉沙池冲沙是复杂的固—液两相流瞬态过程,其数值模拟对校核冲沙能力、优化池型和布置等均具有重要意义。利用CFD商用软件FLOW-3D对冲沙池的冲沙过程进行模拟,并通过与物理模型试验进行对比,在确认其可靠性的基础上,以某水电站实际沉沙池为例进行流态和冲沙过程模拟,分析了不同冲沙底板开启方式对冲沙效果的影响。结果表明,沉沙池冲沙从冲沙底板开启段向两侧发展,初始时冲沙速率较快,冲沙量非常大,随后逐渐减小,冲沙也趋于平缓,FLOW-3D软件应用于沉沙池冲沙过程模拟可行,能较好地反映沉沙池冲沙过程中沙粒的运动规律。

The flushing process of sedimentation basins is a complicated unsteady solid-liquid two-phase flow,and its numerical simulations are important for verifying flushing ability and optimizing shape and layout of the basin.This study tries to simulate this transient flushing process by the commercial CFD software FLOW-3D.First the sediment settling and and scouring models are introduced,and their accuracy and feasibility are validated by comparing the numerical results with the measured data of an existing model test.After that,the flow and flushing process of a practical sedimentation basin are simulated and analyzed.The influences of different opening schemes of the flushing orifices at the bottom of the basin are discussed.The results show that the flushing process started from the opening part to its sides.At initial moment,the flushing rate is fast and a large amount of sand is flushed away.Then the flushing rate is gradually reduced and tend to be gentle.The results also show that the application of commercial CFD software FLOW-3Dto the numerical simulation of flushing process is feasible and the motion regularity of the sands in the process of flushing process is well manifested.