Distribution and Deposition of Cylindrical Nanoparticles in a Turbulent Pipe Flow
Distribution and Deposition of Cylindrical Nanoparticles in a Turbulent Pipe Flow
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DOI：
10.3390/app11030962
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发表时间：
2021-01
期刊：
影响因子：
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通讯作者：
Wenqian Lin;Ruifang Shi;Jianzhong Lin
中科院分区：
文献类型：
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作者：
Wenqian Lin;Ruifang Shi;Jianzhong Lin
对圆管湍流中柱状纳米颗粒的分布和沉积进行了数值研究。包括颗粒的影响的湍流方程求解与颗粒数密度的平均方程和颗粒取向的概率密度函数，包括布朗和湍流扩散的组合效果。结果表明，颗粒浓度沿流动方向呈沿着不均匀分布，且随着颗粒长径比和雷诺数的增大，颗粒浓度分布的不均匀性减小。随着颗粒长径比的增大和雷诺数的减小，越来越多的颗粒沿其长轴向靠近流动方向排列。近壁区的颗粒沿流动方向排列明显，而在靠近管道中心的区域，颗粒只出现轻微的择优取向。颗粒的穿透效率随颗粒长径比、雷诺数和管长径比的增大而减小。最后，根据数值计算结果，建立了颗粒侵彻效率与相关综合参数之间的关系。
Distribution and deposition of cylindrical nanoparticles in a turbulent pipe flow are investigated numerically. The equations of turbulent flow including the effect of particles are solved together with the mean equations of the particle number density and the probability density function for particle orientation including the combined effect of Brownian and turbulent diffusion. The results show that the distribution of the particle concentration on the cross-section becomes non-uniform along the flow direction, and the non-uniformity is reduced with the increases of the particle aspect ratio and Reynolds number. More and more particles will align with their major axis near to the flow direction, and this phenomenon becomes more obvious with increasing the particle aspect ratio and with decreasing the Reynolds number. The particles in the near-wall region are aligned with the flow direction obviously, and only a slight preferential orientation is observed in the vicinity of pipe’s center. The penetration efficiency of particle decreases with increasing the particle aspect ratio, Reynolds number and pipe length-to-diameter ratio. Finally, the relationship between the penetration efficiency of particle and related synthetic parameters is established based on the numerical data.