壁面温升对近壁流场及污染物扩散影响

Study of Building Facades Temperature-rise Effect on Near-wall Wind Field and Pollutant Dispersion

为研究太阳辐射导致的壁面温升对高层建筑近壁面流场及污染物扩散的影响,本文针对不同壁面及环境温度条件进行了分析。先根据日本建筑学会提供的风洞实验数据进行了对比,选用3种RANS湍流模型对室外高层建筑绕流流场进行了模拟。模拟结果与风洞实验数据对比发现Realizable k-ε模型的结果与实验数据更接近。基于此结论,应用Realizable k-ε模型,对建筑壁面在不同温升情况下的近壁流场及污染物扩散进行比较。结果表明,太阳辐射下壁面温度高于环境温度时,近建筑壁面处风速会增加,污染物更易在背风面底层处堆积。该结果有助于高层建筑自然通风设计优化,同时可为高层住宅居民开窗行为提供指导。

Aiming at evaluating how the solar radiation effects the wind field and the pollutant dispersion around building,a series of numerical studies were conducted under different temperature differences. Three turbulence models are employed to simulate the outdoor wind field around a high-rise building model, and the simulation results were compared with the wind tunnel experimental data provided by the Architectural Institute of Japan(AIJ). It was found that the results of the Realizable k-ε model were closer to the experimental data. Based on this validation study, the Realizable k-ε model was used to simulate the flow field and pollutant dispersion under different temperature rises. The results suggested that when there is a temperature rise in the facades relative to the ambient air due to the solar radiation effect, the wind speed close to the wall will increase in lateral face, Beside, the pollutant will stack more easily at the bottom of leeward side.