关键词: 环境工程, 背风壁面, 热流密度, 热泳力, 数值模拟

Abstract: A physical model was established by choosing some residential area as example to study the pollutant of fine particles existing in vehicle exhaust gas. Based on three-dimensional turbulant model and by use of CFD software, air flow field surrounding window-opened building under such conditions of different leeward wall surface heat flow density, under different wind velocity and different wind loading cases was simulated and calculated by numerical model.The law of the particle concentration distribution under different situations was analyzed. The results show that for the window-opened building with its leeward wall surface with heat flow, yaw wind facilitates more in transporting the particle pollutants along with the wind from interior of building street to outside the building area. A certain critical value exists for wind effect in diluting particles at different locations and any exceeding of the critical value will block the spreading of the particles. The thermal effect field formed by leeward wall surface heat flux and impact on pollutants vary depending on wind speeds. In case of smaller wind speed, the spreading of particle pollutants primarily is driven by thermophoretic force, while for greater wind speed, the wind field dominats.

Key words: environment engineering, leeward, heat flux density, thermophoretic force, numerical simulation