防风网阻力系数的计算方法研究

发布时间：2018-03-06 18:34

  本文选题：防风网　切入点：阻力系数　出处：《青岛科技大学》2017年硕士论文　论文类型：学位论文

【摘要】：防风网抑尘工程技术是防治大型露天料堆场二次扬尘的有效措施,其核心部件为防风网,而有关防风网的受力计算目前尚未形成专门的规范,此值直接关系到钢构架的结构设计,对于工程建设具有重要的指导意义。本文利用FLUENT软件进行不同开孔率对平面型、蝶形防风网尾流区内流场特性影响的数值模拟,并与PIV实验数据的相比较,验证了数值模型的合理性与正确性。在此基础上,开展了来流风速、开孔率和开孔直径对平面型、蝶形防风网受力影响的数值模拟。研究结果表明:(1)平面型、蝶形防风网的阻力系数随着来流风速增加逐渐减小,而当来流风速大于10.0m/s时,它们的阻力系数基本不随来流风速的增加而变化,考虑到防风网工程建设中,来流风速的选取一般是基于当地50年内的最大风速,其值通常大于10.0m/s。因此,忽略来流风速的变化对阻力系数的影响;(2)当来流风速和开孔直径不变时,平面型防风网的阻力系数随开孔率的增加呈指数减小的趋势,其拟合公式:当d=6mm,0＜(?)≤0.353时,cd=2.342(1-(?)2.652);当来流风速和开孔率不变时,平面型防风网的阻力系数随开孔直径的增加呈非线性减小的趋势,其拟合公式:当4mm≤d≤12mm时,cd((?)=0.264)=2.838-0.171d+0.0156d2- 0.00048d3;(3)蝶形防风网纵向间距对阻力系数的影响与开孔率有关,在较小开孔率时,纵向间距对阻力系数的影响小于开孔直径对阻力系数的影响,而在较大开孔率时,纵向间距对阻力系数的影响大于开孔直径对阻力系数的影响;横向间距对阻力系数的影响小于开孔直径对阻力系数的影响;(4)出于减小蝶形防风网受力考虑,在相同网孔排列形式和开孔率的情况下,优选开孔直径较大的蝶形防风网;(5)通过对数值结果进行拟合方程得到蝶形防风网阻力系数的计算式:当6.6mm≤d≤9.5mm,0＜(?)≤0.367时cd=k(?)+2.280其中k=0.00185-0.030d-0.0067d2
[Abstract]:The anti-dust engineering technology of windproof net is an effective measure to prevent and cure the secondary hoisting dust in large open-air material storage yard. Its core component is the wind-proof net, but the force calculation of the wind-proof net has not yet formed a special specification. This value is directly related to the structural design of the steel frame and has important guiding significance for engineering construction. In this paper, the numerical simulation of the influence of different opening rates on the characteristics of flow field in the wake zone of plane and butterfly windbreakers is carried out by using FLUENT software. Compared with the experimental data of PIV, the rationality and correctness of the numerical model are verified. Numerical simulation of the force effect of butterfly windbreak network. The results show that the drag coefficient of butterfly windbreak network decreases gradually with the increase of incoming wind speed, and when the incoming wind speed is greater than 10.0 m / s, the resistance coefficient of butterfly windbreak network decreases gradually with the increase of incoming wind speed, and when the wind speed is greater than 10.0 m / s, Their drag coefficient basically does not change with the increase of wind speed. Considering that in the construction of windbreak network, the selection of wind speed is usually based on the maximum local wind speed in 50 years, and its value is usually greater than 10.0 m / s. Ignore the effect of the change of the wind speed on the drag coefficient. When the wind speed and the diameter of the orifice are invariant, the resistance coefficient of the planar windscreen decreases exponentially with the increase of the opening rate. The fitting formula is as follows: when the inlet velocity and the diameter of the hole are not changed, the resistance coefficient of the planar windbreak mesh decreases exponentially. ) 鈮，

本文编号：1576002