摘要
随着我国城市汽车保有量的迅速攀升,城市中心区域的空气质量与生态环境急剧恶化.利用计算流体力学(CFD)数值模拟,研究了3种H/W(街道建筑物高度/峡谷宽度)下高架桥对街道峡谷内颗粒物扩散的影响.建立了街道峡谷内机动车尾气中颗粒物扩散模型,并给出了边界条件.采用标准k-ε模型与离散相模型对街道峡谷内部气流运动、颗粒物扩散及浓度分布进行了模拟计算,并计算了高架桥对风场及颗粒物扩散的影响.结果表明:H/W越大,街道峡谷内颗粒物浓度越高,同时颗粒物平均滞留时间越长.相对于没有高架桥的街道峡谷,高架桥附近区域风场变化明显,但对建筑物墙壁、地面及峡谷顶层处影响较小.街道峡谷内存在高架桥时,在墙壁较低处颗粒物浓度增加.
Due to the increase of private vehicles in cities in China,high-level pollution is often detected in urban street canyons.Using a two-dimensional computational fluid dynamics（CFD） model,the environmental impacts of viaducts on the wind flow and dispersion of particles were studied under three different heightwidth ratios（H/W） of street canyons.Two-dimensional flow and dispersion of particles from traffic exhaust were modeled using the standard k-ε turbulence and discrete phase models.The results revealed that increasing the H/W effectively raised the particle concentration and mean particle residence time.The airflows were obviously disturbed at the region around the viaduct,whereas there was no significant change of the airflows near the walls of the buildings,the ground and the roofs of the canyon.The particle concentration at the lower part of the walls increases when a viaduct exists in the street canyons.
出处
《环境科学研究》
EI
CAS
CSCD
北大核心
2012年第2期159-164,共6页
Research of Environmental Sciences
基金
中国科学院知识创新工程重要方向性项目(KJCX3-SYW-N3)
国家自然科学基金项目(11079049,11005141)
