温度层结条件下气载污染物迁移扩散规律

The atmospheric temperature stratification conditions directly affect the turbulence and thermal characteristics of near-surface atmospheric boundary layer, but also affect the transport and diffusion of airborne radioactive pollutants released by nuclear facilities. The project would study the similarity criteria of wind tunnel simulation experiments for atmospheric thermal boundary layers under different scales, propose the coupled dynamic regulation method of atmospheric turbulence and thermal parameters and the construction method of cushions in the complex thermal environment near the ground, and establish wind tunnel simulation experimental methods under different stratification conditions; A wind tunnel simulation experiment was conducted to study the effect of steady-state atmospheric environment parameters on the diffusion parameters, range, and concentration distribution of airborne radioactive pollutants; The atmospheric parameters and the thermal parameters of the underlying surface are dynamically regulated to study the transport and diffusion polymorphic characteristics and evolution of airborne radioactive pollutants under different stratification conditions; a multi-region and multi-model coupled numerical wind tunnel model for complex atmospheric boundary conditions was studied, and the numerical wind tunnel was built based on applicant's proprietary intellectual property software FFSV and open source platform "OpenFOAM" to extend the results of small-scale wind tunnel experiments to the study of airborne pollutant diffusion under real original scale complex atmospheric boundaries condition, and to obtain the migration and diffusion rule of airborne radioactive pollutants in the original scale temperature stratification condition.This study will have important scientific value for establishing wind tunnel experiments and numerical wind tunnel methods, and mastering the migration and diffusion of airborne pollutants at different temperatures.

大气温度层结直接影响近地面大气边界层湍流与热力特性，还将影响气载放射性污染物的迁移扩散规律。本项目将研究不同缩比例尺大气热边界层风洞模拟实验的相似准则，提出大气湍流与热力参数的耦合动态调控方法和下垫层复杂热力环境的营造方法，建立不同层结风洞模拟实验研究方法；采用风洞实验研究稳态大气环境参数对气载放射性污染物的扩散参数、范围和浓度分布的影响规律；动态调控大气环境参数和下垫面热力参数，研究不同层结条件下气载放射性污染物迁移扩散的多态特性及其演化规律；研究复杂大气边界多区域、多模型耦合的数值风洞数学模型，基于申请者自主知识产权软件FFSV和开源平台“OpenFOAM”建立数值风洞，把缩比例风洞实验结果拓展到真实原尺度复杂大气边界气载污染物扩散规律研究中，得出原尺度温度层结条件气载放射性污染物迁移扩散规律。本研究对建立风洞实验和数值风洞方法，掌握不同温度层结气载污染物迁移扩散规律有重要的科学价值。

大气温度层结直接影响近地面大气边界层湍流与热力特性，还将影响核设施向环境中排放的气载污染物在大气中迁移扩散。本研究瞄准影响气载污染物迁移扩散的几类关键要素，针对温度层结条件下气载污染物在大气中迁移扩散进行研究。首先，结合现场示踪试验和物理风洞实验方法分析了示踪气体在大气中迁移扩散的时空分布规律；其次，根据质量守恒定律、牛顿第二定律、能量守恒定律和物质守恒定律，应用数学建模方法构建了温度层结条件下气载污染物在大气中迁移扩散的数学模型，并利用实验数据对其进行验证和修正，揭示了温度层结条件下气载污染物在大气中的迁移扩散机理；再其次，根据修正的数学模型，利用开源程序OpenFOAM开发了温度层结条件下气载污染物迁移扩散求解程序。进一步，采用数值模拟方法探究了多因素和多因素耦合条件下气载污染物大气迁移扩散规律；最后，基于开源程序WRF和OpenFOAM开发了真实原尺度气载污染物迁移扩散计算平台。本研究对丰富和完善温度层结条件下气载污染物迁移扩散机理，保护环境安全具有重要的意义。