离散相模型下公路风沙流数值模拟

发布时间：2018-01-13 13:02

本文关键词：离散相模型下公路风沙流数值模拟　出处：《兰州大学》2015年硕士论文　论文类型：学位论文

【摘要】：在西部地区公路发挥着无可替代的巨大作用,而该地区由于气候和自然条件制约,公路建设和养护一直面临着巨大的挑战。本文利用流体动力分析软件Fluent,针对路堤、路堑和半路堑三种不同断面形式的公路路基风场进行了数值模拟,从力学角度解释了公路易受风蚀破坏和沙埋的原理。通过对不同参数断面风场特征的对比,提出了比较合理的公路断面设计要求。而后通过设置挡风墙,利用离散相模型,计算分析了沙粒在风场中的运动特性,并通过对比得出了挡风墙的合理高度,为工程实际建设提供一些参考。本文主要研究内容分为两部分：1.对路堤、路堑和半路堑三种不同断面形式公路风场进行数值模拟,从力学角度分析了路堤路堑断面易发生风蚀沙埋危害的原因,同时通过对不同参数断面风场的对比,提出了路基设计要求：高度(深度)不宜过大,边坡比应尽量取较小值,本文模型中该值为1：4,据此为公路断面建设提供建议。2.利用离散相动力模型,设置挡风墙后模拟了沙粒的运动,统计分析得到了如下结论：风场一定时,随着沙粒粒径的增大,挡风墙对沙粒的阻挡作用逐渐增强；随着摩阻风速的变大,挡风墙对沙粒的阻挡作用逐渐减弱；改变来流风向,挡风墙对沙粒的阻挡作用亦随之改变；挡风墙对沙粒的阻挡作用随着挡风墙高度的变大而增强,从计算上看,存在一临界高度2.5m。当挡风墙为透风式时,模拟发现该形式下开孔大小和位置均会对风场和沙粒产生一定的影响。
[Abstract]:Roads play an irreplaceable role in the western region, which is constrained by climate and natural conditions. Highway construction and maintenance have been faced with great challenges. This paper uses fluid dynamic analysis software Fluent. aiming at embankment. The wind field of highway roadbed with three different cross sections of cutting and half cutting is numerically simulated, and the principle of highway being liable to wind erosion and sand burial is explained from the angle of mechanics. The characteristics of wind field of different parameters are compared. The reasonable design requirements of highway section are put forward. Then, by setting the windshield wall and using the discrete phase model, the movement characteristics of sand particles in the wind field are calculated and analyzed, and the reasonable height of the windshield wall is obtained by comparison. The main contents of this paper are divided into two parts: 1. Numerical simulation of wind field in three different cross-section forms of embankment, cut and half cut is carried out in this paper. In this paper, the causes of wind erosion and sand burying in the cutting section of embankment are analyzed from the point of view of mechanics. At the same time, through the comparison of wind fields of different parameters, the design requirements of roadbed are put forward: the height (depth) should not be too large. The slope ratio should be taken as small as possible, the value of this model is 1: 4, according to this model to provide suggestions for highway cross-section construction .2.Using discrete phase dynamic model, the movement of sand particles is simulated after setting the windshield wall. The results of statistical analysis are as follows: when the wind field is fixed, the blocking effect of the windshield wall on the sand grain increases with the increase of the sand particle size; With the increase of frictional wind speed, the barrier effect of windshield wall to sand gradually weakens. Changing the direction of the incoming flow wind, the barrier effect of the windshield wall to the sand particles is also changed. The barrier effect of the windshield wall to the sand particles increases with the height of the windshield wall. From the calculation, there is a critical height of 2.5m. when the windshield wall is air-permeable. It is found that the size and location of the holes in this form will have a certain effect on the wind field and sand particles.
【学位授予单位】：兰州大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U412

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