School of Environment and Architecture, University of Shanghai for Science and Technology, No. 516, Jungong Road, Yangpu District, Shanghai, 200093, China.
Natural Science Center, Kim Il Sung University, Taesong District, Pyongyang, Democratic People's Republic of Korea.
Environ Sci Pollut Res Int. 2024 May;31(22):31818-31842. doi: 10.1007/s11356-024-33343-5. Epub 2024 Apr 19.
Building envelope features (BEFs) have attracted more and more attention as they have a significant impact on flow structure and pollutant dispersion within street canyons. This paper conducted CFD numerical models validated by wind-tunnel experiments, to explore the effects of the BEFs on characteristics of the airflow and pollutant distribution inside a symmetric street canyon under perpendicular incoming flow. Three different BEFs (balconies, overhangs, and wing walls) and their locations and continuity/discontinuity structures were considered. For each canyon with various BEFs, the air exchange rate (ACH), airflow patterns, and pollutant distributions were evaluated and compared in detail. The results show that compared to the regular canyon, the BEFs will reduce the ACH of the canyon, but increase the disturbances (the proportion of ACH') inside the canyon. The BEFs on the leeward wall have the least influence on the in-canyon airflow and pollutant distributions, followed by that on the windward wall. Then when the BEFs are on both walls, the ventilation capacity of the canyon is weakened greatly, and the pollutant concentration in the ground center is increased significantly, especially near the windward side. Moreover, the discontinuity BEFs will weaken the effect of the continuity BEFs on the in-canyon flow and dispersion, specifically, the discontinuity BEFs reduced the region of high pollutant concentration distributions. These findings can help optimize the BEFs design to enhance ventilation and mitigate traffic pollution.
建筑围护结构特征（BEF）对街道峡谷内的流场结构和污染物扩散有显著影响，因此越来越受到关注。本研究通过风洞实验验证了 CFD 数值模型，以探讨在垂直来流条件下，对称街道峡谷中 BEF 对气流特性和污染物分布的影响。考虑了三种不同的 BEF（阳台、挑檐和翼墙）及其位置和连续性/非连续性结构。对于具有各种 BEF 的每个峡谷，详细评估和比较了空气交换率（ACH）、气流模式和污染物分布。结果表明，与规则峡谷相比，BEF 会降低峡谷的 ACH，但会增加峡谷内的干扰（ACH'的比例）。背风墙上的 BEF 对峡谷内气流和污染物分布的影响最小，其次是迎风墙上的 BEF。然后，当两侧都有 BEF 时，峡谷的通风能力大大减弱，地面中心的污染物浓度显著增加，特别是迎风侧附近。此外，不连续的 BEF 会削弱连续的 BEF 对峡谷内流动和扩散的影响，特别是不连续的 BEF 减少了高污染物浓度分布的区域。这些发现有助于优化 BEF 设计，以增强通风并减轻交通污染。
