城市空间结构对汽车尾气扩散影响规律研究

Study on Influence Laws of Urban Space Structure on Automobile Exhaust Diffusion

为了研究城市空间结构对汽车尾气扩散的影响,参考高分变率遥感影像建立了某城市核心区域几何模型。以当地常年气象风向作为重要的边界条件之一,应用CFD多相流技术,模拟了十字交叉口车辆队列怠速等候35 s时的尾气扩散过程。结果表明,在空间狭小区域,近地空间CO体积分数达10-7,与研究域平均体积分数相差100倍以上,说明城市空间结构对尾气扩散影响较大。建筑设计时应结合当地气象风向和风速,设计一定的建筑高度梯度,以利于污浊气体迅速扩散至远地空间。

For studying the influence laws of urban space structure on the automobile exhaust diffusion, the core region solid geometry model for one urban is set up based on high resolution remote sensing image. Regarding meteorological wind as an important boundary conditiom and using CFD and multiphase flow, a crossroads vehicle queue exhaust diffusion process dur- ing 35 s of idle waiting is simulated. The results indicate that, in limited space, CO volume fraction near- Earth space is up to 10e-7 and mere than 100 times average value of the entire study area, so urban space structure greatly influences automo- bile exhaust diffusion. It is proposed that local meteorological wind direction and speed should be considered and different height gradient design should be selected in buildings structural layout, so that the exhaust can spread rapidly and drift to the urban high altitude.