风沙二相流动的三流体模型*
A Three-Fluid Model of the Sand-Driven Flow
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摘要: 本文来用连续介质观点研究风沙运动,这一工作的关键在于如何正确地模化颗粒相的应力。通过对气-团二相流研究中常用的双流体模型的分析,我们发现此模型在研究风沙运动时有相当的缺陷,即使是研究最简单的风沙流──定常二维充分发展的流场也是如此。基于此,我们提出了将向上、向下运动的颗粒用两种拟流体来表征的三流体模型。相对于双流体模型,三流体模型较好地反映了流场的内部结构及边界状况对流动的影响,而且固相应力的主要部分也可用应变量显式表示。对近似求解相当有利。最后,本文给出了三流体模型的风沙流运动方程组并讨论了相应的边界条件的提法。Abstract: The sand-driven flow is studied from the continuum viewpoint in this paper. The crux of this work is how to model the stresses of the particle phase properly. By analysing the two-fluid model which usually, works in solving gas-particle two-phase. flow,. we find that this model has many. deficiencies for studying the sand-driven flow,even for the simplest case-the steady, two-dimensional fully-developed flow.Considering this, we have proposed the three-fluid model in which the upward particles and the downward-particles ore regarded as two kinds of fluids respectively.It is shown that the three-fluid model is better than the two-fluid model in reflecting the internal structure of the flow, region and the influence of the boundary situations on the flow. and it is advantageous to find an approximate solution in that the main components of the particle-phase stresses can be explicitly expressed by those variables in the three-fluid model.In the end, the governing equations as well as the boundary. conditions for the three-fluid model are provided with a discussion.
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Key words:
- Sand-driven flow /
- two-phase flow /
- two-fluid model /
- three-fluid model
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