A numerical study of air pollutant dispersion with bimolecular chemical reactions in an urban street canyon using large-eddy simulation
A numerical study of air pollutant dispersion with bimolecular chemical reactions in an urban street canyon using large-eddy simulation
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DOI：
10.1016/j.atmosenv.2012.02.039
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发表时间：
2012-07-01
影响因子：
5
通讯作者：
Ooka, Ryozo
中科院分区：
文献类型：
--
作者：
Kikumoto, Hideki;Ooka, Ryozo
本文对纵横比为1.0的二维城市街道峡谷中化学反应性空气污染物的湍流扩散进行了大涡模拟。设置在街道峡谷底部的线源排放的一氧化氮分散并与自由流中包含的臭氧反应。这些反应对峡谷空间中污染物的浓度有显著的影响，它们使反应产物的浓度相对于反应物的浓度增加。大气污染物通过峡谷上方自由剪切层的输送与湍流结构密切相关。当峡谷上方出现低速区时，峡谷中的气体主要被耗尽。相反，自由流中的污染物以高速流体流入峡谷。因此，反应物浓度的时间波动之间的相关性强烈地影响自由剪切层附近区域的反应速率。在该计算中，相关项在最大值处达到平均反应速率的20%的值。(C)2012爱思唯尔有限公司保留所有权利。
A large-eddy simulation is performed on a turbulent dispersion of chemically reactive air pollutants in a two-dimensional urban street canyon with an aspect ratio of 1.0. Nitrogen monoxide emitted from a line-source set on the bottom of the street canyon disperses and reacts with Ozone included in a free stream. The reactions have significant influences on the concentrations of pollutants in the canyon space, and they increase the concentrations of the reaction products relative to of the concentrations of the reactants. The transport of air pollutants through a free shear layer above the canyon is closely related to the structure of the turbulence. Gases in the canyon are mainly exhausted when low-speed regions appear above the canyon. In contrast, pollutants in the free stream flow into the canyon with high-speed fluid bodies. Consequently, the correlation between the time fluctuations of the reactants' concentrations strongly affects the reaction rates in the region near the free shear layer. In this calculation, the correlation term reaches to a value of 20% of the mean reaction rate at a maximum there. (C) 2012 Elsevier Ltd. All rights reserved.