Wind tunnel tests of inter-flat pollutant transmission characteristics in a rectangular multi-storey residential building, part A: Effect of wind direction

The inter-flat dispersion of hazardous air pollutants in residential built environment has become a growing concern, especially in crowed urban areas. The purpose of present study is to investigate the wind induced air pollutant transmission and cross contamination routes in typical buildings. In this paper, a series of experiments was carried out in a boundary layer wind tunnel using a 1:30 scaled model that represented the typical configuration of rectangular multi-storey residential buildings in Shanghai. Sulfur hexafluoride (SF6) was employed as tracer gas in the wind tunnel tests. The conditions under two ventilation modes, i.e. single-sided natural ventilation and cross natural ventilation, were compared. The tracer gas concentration distributions under four approaching wind angles were monitored and analyzed. Computational Fluid Dynamics (CFD) method was adopted to assist in analyzing airflow patterns. The experiment results elucidated that in the two ventilation scenarios, both of the vertical and horizontal inter-flat airborne transmission could proceed. The wind direction played a key role on the pollutant concentration distribution. Compared with the single-sided ventilation mode, cross ventilation could weaken the air pollutant dispersion along the vertical direction when the contamination source was on the windward or on the leeward unit. When the wind blowing parallelly to the source unit window, namely the source room was on the sideward, cross ventilation would not suppress the vertical transport on one hand, but reinforce the horizontal transmission on the other hand. The study is helpful for the analysis of infection risk of respiratory diseases in the residential buildings. (C) 2016 Elsevier Ltd. All rights reserved.

居住建筑环境中有害空气污染物在楼层间的扩散已成为人们日益关注的问题，在拥挤的城市地区尤其如此。本研究的目的是调查典型建筑中由风引起的空气污染物传播和交叉污染路径。本文利用一个1:30的缩尺模型在边界层风洞中进行了一系列实验，该模型代表了上海矩形多层住宅建筑的典型构造。在风洞试验中，采用六氟化硫（SF6）作为示踪气体。对两种通风模式，即单侧自然通风和交叉自然通风的情况进行了比较。监测并分析了四种来流风角度下示踪气体的浓度分布。采用计算流体动力学（CFD）方法辅助分析气流模式。实验结果表明，在这两种通风情形下，垂直和水平方向的楼层间空气传播都可能发生。风向对污染物浓度分布起着关键作用。与单侧通风模式相比，当污染源位于迎风或背风单元时，交叉通风可减弱空气污染物沿垂直方向的扩散。当风平行于污染源单元窗户吹时，即污染源房间位于侧面，交叉通风一方面不会抑制垂直传输，另一方面会加强水平传输。这项研究有助于分析住宅建筑中呼吸系统疾病的感染风险。（C）2016爱思唯尔有限公司。保留所有权利。