【作者】 谢艳芳；

【导师】 陈刚； 王颖；

【作者基本信息】 西安理工大学 ， 水力学及河流动力学， 2005， 硕士

【摘要】 自然界的河流中常常携带着泥沙,这不仅给生产带来一系列的问题,也引起了很多的环境问题。而研究泥沙运动及分布规律是解决这些问题的前提和条件。多年来人们对此问题作了多途径的探索,取得了大量的研究成果,但远未达到完美的程度。因而进一步展开对泥沙运动及分布问题的研究是非常必要的。近几年来紊流数值模型及多相流理论在泥沙输移及分布计算中开始应用,但尚不多见。本文将从多相流理论出发,探讨多相混合模型在低含沙水流中的应用。 论文首先对研究过程中所用到的单相流和多相流混合模型进行了必要的介绍,并对所用的计算软件及模型所采用的数值方法作了说明和选择。 其次,采用了在玻璃水槽中进行的低含沙水流实验对模型进行了验证。模型对分别携带三类泥沙颗粒的水流进行了模拟。通过对水槽中部横截面处挟沙水流的流速和紊动强度的计算值与实验结果对比可知:流速的计算值与实测值相差不大;随着水流中极细颗粒和较粗颗粒的增加,紊动强度计算值的变化趋势同实验结论相同,但对于中径颗粒的增加,紊动强度的计算值却没有反映出实验中所存在的制紊现象。然后进一步在浓度相同的两种水力条件下,对不同粒径泥沙加入后的水流结构及泥沙分布状况进行了模拟计算,并对水流中的泥沙分布作了定性分析,认为其结果符合一股规律。经上分析认为该多相流混合模型在一定程度上可以反映挟沙水流的性质和状况。西安理工大学硕士学位论文 最后利用单向流模型和多相流混合模型模拟了鸭子荡水库的水流及泥沙运动状况,显示了不同粒径的泥沙颗粒在水库中的分布情况以及出口处泥沙的体积分数。由计算结果可知,随着泥沙粒径的增大,泥沙沉降越明显,水流挟沙能力相对越弱,泥沙越易在上游淤积,出口处的泥沙越少。关键词:多相流混合模型低含沙水流泥沙分布体积分数数值模拟更多还原

【Abstract】 Sediment transport in river not only brings trouble with production, but also with environment. Studying movement and distribution of sediment in the flow is precondition to solve the problem. Sediment transport has been studied by a lot of researchers, and a great deal of research results have been obtained, but it is not perfect. So, it is necessary to further study movement and distribution of sediments in the flow. In last years, the theory for multiphase flow, which combines turbulence model, was applied to the sediment transport, but infrequent. From this aspect, the application of the mixture model for multiphase flow to the flow at low sediment concentration would be studied in this thesis.In the thesis, the model for one-phase flow and the mixture model for multiphase flow used were be introduced, and computational software was explained and numerical methods were chose.The model was validated by comparing with experiment’s result of sediment-carried water at low sediment concentration in flume. The flow carried sediments with three different diameters respectively was simulated. After comparing computational dates and experimental results of velocity and turbulent intensity at cross section in the middle of flume, some results are concluded: the computational results of velocity of flow coincide well with the measured data; the variational trend of turbulent intensity computational andexperimental results is same along with sediments whose diameters are smaller and bigger increased in the flow , but is different along with sediment increased whose diameters are between both kinds above. Then, two kinds of flow whose concentration was same carried sediments with different diameters were simulated, the qualitative analysis of distributing of sediments was done and considered reasonable. So, the mixture model for multiphase flow was considered that it can simulate characters of the flow carried sediments to some extend.The flow and movement of sediments of Yazidang Reservoir were simulated with the model for one phase flow and the mixture model for multiphase flow. And distribution in the reservoir and volume fraction at the outlet of sediments with different diameters were displayed. From the computational result, it was the conclusions that sedimentation is more obvious, the capability of the flow carrying sediments becomes weaker, and sediments filled up easier when the diameter of sediments becomes bigger.更多还原