基于DPM模型的街谷内颗粒物扩散特性研究

Study of aerosol dispersion in urban street canyon based on DPM model

通过采用离散相模型(DPM),对等高对称街谷和非等高不对称街谷在参考风速Zref=2m/s时,粒径dp=10μm的固体颗粒物在街谷内的扩散分布进行了数值研究.计算湍流模型选用重正化群两方程模型,计算结果表明在城市风场作用下会导致街谷内空气呈漩涡流动,街谷几何形状变化影响街谷内污染物浓度分布,且在深街谷(B/H=0.5)和上游建筑高于下游建筑的非对称街谷(H1/H2=2)中街谷内空气颗粒无量纲浓度远高于同类型其它几何尺寸街谷.

Based on discrete phase model（DPM）, a simulation was carried out to study the aerosols with diameter of 10 microns dispersed in different kinds of geometrical street canyons when referenced wind velocity Zref = 2m/s. In the simulation, renormalization group k-ε two equations model was used as turbulence model. The numerical results indicated that due to urban wind field the air in the street canyon presents vortex＇ s flow; street canyon aspect dimension ratio have crucial effect on the aerosol concentration distributing. Moreover, the nondimensional concentration of the street canyon with the aspect ration of B/H = 0.5 and H1/H2 = 2 is more dense than others.