隧道通风阻力格栅等效摩阻模拟研究

发布时间：2018-07-12 14:09

本文选题：公路隧道 + 阻力格栅　；参考：《长安大学》2015年硕士论文

【摘要】：隧道通风物理模型试验中,由于试验场地和试验条件的限制,通常难以建立1:1比例模型或同比尺缩小模型。考虑到通风模型试验往往是对局部复杂部位进行研究,在保证原型与模型阻力相似的前提下,采用变率模型可以有效缩短隧道通风模型长度。在隧道模型试验中设置阻力格栅缺少系统的理论支持,同时如何选取和设置阻力格栅值得研究。基于以上问题,本文针对阻力格栅进行了深入研究。1.介绍了隧道通风物理模型试验的相似准则和自模区理论,以此为基础,阐述了阻力格栅的等效作用原理及作用分类,推导出了阻力格栅局部阻力损失系数ξ的计算公式以及阻力格栅等效模型长度Lm的计算公式,并阐述了阻力格栅模型的适用性。2.采用计算流体力学软件Fluent对不同孔数的阻力格栅流场进行模拟研究,研究结果表明,当有效面积比一定时,阻力格栅的孔数越多,其均流作用越显著,风流波动逐渐降低,上下游影响长度显著减小。阻力格栅孔数大于500时,其上下游影响总长度小于3倍模型当量直径。3.通过物理模型试验研究阻力格栅串联间距、串联数量的影响以及阻力损失系数,为阻力格栅的选取和设置提供指导建议,同时介绍阻力格栅在隧道通风模型试验中的具体应用。试验结果表明,模型加入阻力格栅后,仍然存在自模区,其临界风速与模型的临界风速近乎相等;阻力格栅的串联间距、组数、规格对模型进入自模区的临界风速几乎没有影响;每组格栅局部阻力损失系数随格栅组数的增多而降低,降低的速率随着格栅组数的增多而减小;阻力格栅串联间距应不小于三倍模型当量直径。
[Abstract]:In the physical model test of tunnel ventilation, due to the limitation of test site and test conditions, it is usually difficult to establish the 1:1 scale model or the scale reduction model. Considering that the ventilation model test is usually to study the local complex parts, the model length of tunnel ventilation can be effectively shortened by using the variable rate model on the premise that the prototype is similar to the model resistance. It is necessary to study how to select and set resistance grille in tunnel model test, which lacks the theoretical support of the system. Based on the above problems, the resistive grille is studied in this paper. This paper introduces the similarity criterion and self-model zone theory of physical model test of tunnel ventilation. Based on this, the equivalent action principle and action classification of resistance grille are expounded. The formula of local resistance loss coefficient 尉 and the length of resistance grid equivalent model L m are derived, and the applicability of resistance grid model is expounded. The flow field of resistance grille with different number of holes is simulated by fluent. The results show that when the effective area ratio is fixed, the more the number of holes in resistance grille is, the more the average flow is, and the fluctuation of wind flow decreases gradually. The influence length of upstream and downstream decreases significantly. When the number of resistance grille holes is greater than 500, the total length of the upstream and downstream influences is less than 3 times the equivalent diameter of the model. Through the physical model test, the influence of the series distance, the number of series and the coefficient of resistance loss of the resistance grille are studied, which provides guidance suggestions for the selection and setting of the resistance grille. At the same time, the application of the resistance grille in the tunnel ventilation model test is introduced. The experimental results show that the self-mode region still exists after the resistance grille is added to the model, and the critical wind speed is almost equal to the critical wind speed of the model. The local drag loss coefficient of each grid decreases with the increase of the number of grid groups, and the decreasing rate decreases with the increase of the number of grid groups. The resistance grid in series should not be less than three times the equivalent diameter of the model.
【学位授予单位】：长安大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U453.5

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