State Key Laboratory of Fire Science, University of Science and Technology of China, Hefei 230027, PR China.
J Hazard Mater. 2011 Sep 15;192(3):1623-32. doi: 10.1016/j.jhazmat.2011.06.090. Epub 2011 Jul 6.
This article presents experimental results that illustrate the unsteady characteristics of gas dispersion around a complex-shaped high-rise building for different incident wind directions. A series of wind tunnel experiments were conducted using a 1:30 scale model that represented the real structures under study. The objective of this paper is to study the behaviour of concentration fluctuations through transient analysis. Tracer gas was continuously released from a point source located at different positions, and a time series of fluctuating concentrations were recorded at a large number of points using fast flame ionization detectors. The experimental data were analysed to provide a comprehensive data set including variances and associated statistical quantities. Both the unsteady characteristics of the system and their potential practical impact are presented and discussed. Under crowd living conditions, the air pollutant exhausted from one household could probably re-enter into the neighbouring households, traveling with ambient airflow. Such pollutant dispersion process is defined as air cross-contamination in this study. The results indicate that the wind-induced cross-contamination around the studied type of high-rise building should not be overlooked, and the fluctuating concentrations should be paid attention to particularly during the evaluation of a potential contamination risk. This study can help deepen our understanding of the mechanisms of air cross-contamination, and will be useful for implementing optimization strategies to improve the built environments in metropolitan cities such as Hong Kong.
本文展示了实验结果，说明了不同来流风向下复杂形状高层建筑周围气体扩散的非定常特性。使用代表实际研究结构的 1:30 比例模型进行了一系列风洞实验。本文的目的是通过瞬态分析研究浓度波动的行为。示踪气体从位于不同位置的点源连续释放，使用快速火焰电离探测器在大量点记录浓度的时变。对实验数据进行了分析，提供了包括方差和相关统计量在内的综合数据集。呈现并讨论了系统的非定常特性及其潜在的实际影响。在人群居住条件下，一户人家排出的空气污染物可能会随着环境气流重新进入邻近的家庭，这种污染物的扩散过程在本研究中被定义为空气交叉污染。结果表明，不应忽视研究类型的高层建筑周围风引起的交叉污染，并且在评估潜在污染风险时应特别注意浓度波动。本研究有助于加深我们对空气交叉污染机制的理解，并将有助于实施优化策略，以改善香港等大都市的建筑环境。
