庭院式居住组团平面形态对PM2.5扩散的影响

摘要

为缓解目前城市严峻的雾霾这一环境问题,采用实地调研、选点测试与CFD仿真模拟的方法,选取已建成的西安市庭院式居住组团为研究对象.从城市设计角度,提炼具备可比性的各类庭院式居住组团平面布局物理模型,运用实地测试以及CFD模拟建立合理的数值模型,进而对不同庭院式居住组团平面形态进行模拟研究,通过对组团内部及外部空间空气品质的差异分析,定量研究不同平面形态对大气污染物稀释扩散的影响.结果表明:综合考虑垂直方向的湍流特征以及微气候影响下的污染物浓度分布规律,在庭院式组团平面布局中节点式组团空间内部的PM2.5细颗粒扩散最差,最有利的形式为U字式组团,可用的形式为风车式组团和散立式组团.%In order to alleviate the current environmental problem of severe haze in the city, the methods of field investigation, selection test and CFD simulation method were used, and the courtyard housing groups in Xi`an were selected as the research object.From the perspective of urban design, the physical models of comparable plane layouts of courtyard housing groups were refined, and the reasonable numerical model was established by field test and CFD simulation.The simulation study of the plane forms of different courtyard housing groups was carried out.The influences of different forms on the dilution and diffusion of air pollutants were studied quantitatively by analyzing the difference of air quality inside and outside the group.The results show that considering the vertical turbulence characteristics and the distribution law of pollutant concentration under the influence of microclimate, the concentration of PM2.5 fine particles inside node-type group space is the worst in the plane layouts of courtyard housing groups.The U-shaped group is the most favorable form, and the forms of windmill and scattered groups are available.