【摘要】 道路绿化带可以影响街道内的对流传热及传质作用。利用CFD技术耦合多孔介质模型,研究在高宽比为1:2的街谷内,不同道路绿化布置形式(五种)对街道峡谷内对流传热,以及机动车尾气污染物扩散现象的影响。通过对不同情况下,街道内流动结构、温度场和污染物浓度变化的分析表明,地面升温引起Ri=0.47的混合对流,对于街道峡谷通风有一定增强,但不明显。屋顶绿化可降低流经的空气温度,增强街道峡谷内的对流,但屋顶绿化同时降低了入流风速,不利于街道峡谷内通风。街道峡谷内绿化带数量的增加,可明显降低周围空气温度,但对空气流动阻碍作用更加明显,造成街道峡谷内平均流速降低,污染物CO浓度范围增大。更多还原

【Abstract】 The road green belt can affect the convective flow,heat and mass transfer in the street canyon.The CFD technology coupled with porous media model was applied to investigate the effects of the different road green arrangement patterns on the convective heat transfer and vehicle exhaust pollutant diffusion in the street canyon with W/H = 1:2.By analyzing the flow structure,temperature and pollutant distributions under different cases,it was found that the ventilation in the street canyon would be enhanced by the mixed flow(Ri = 0.47)due to the heating ground,but not significantly.The roof greening can reduce the flowing air temperature and enhance the convection in the street canyon,but which also can cause the inflow velocity to get smaller and deteriorate the ventilation.In addition,the increasing green belts will reduce the ambient temperature in the street canyon significantly,but also obstruct the airflow more sharply.Furthermore,it reduced the average velocity in the street canyon to increase the high concentration area of pollutant CO.更多还原