考虑雾的微物理特征条件下的水雾扩散数值模拟研究

A numerical simulation study of atmospheric transport and dispersi-on of the spray with considering the micro-physics characteristic

由于雾滴谱的不易获得 ,传统的水雾扩散研究一般不考虑其滴谱特征 ,而将其雾滴粒径作为常数处理 .为此 ,引入实测的雾滴谱资料 ,考虑水雾在流场中的扩散、蒸发及相变潜热对流场的反馈机制 ,利用三维非线性PBL方程组 ,采用工程上实用的湍流 [E ε]闭合方案 ,建立了一个高分辨率的PBL模式来模拟不同层结下 ,水电站泄洪产生的水雾的扩散及其对环境湿度的影响 .模拟结果表明 ,引入雾滴谱后的水雾扩散范围和相对湿度改变范围与不考虑雾滴谱条件下的相比 ,更接近实测 。

For hard to get the distribution of the droplet size of the fog, the traditional study of the dispersion of the spray regarded the droplet diameter as constant without considering the droplet spectrum characteristic. In this paper, a three dimensional, nonhydrostatic numerical model with high spatial resolution, in which a simple energy closure scheme is employed, has been developed to simulate the spray dispersion over complex terrain. The observed droplet spectrum is considered in model equations. The evaporation, condensation, and diffusion of the spray and moisture are taken into account in model equations. The term of latent heat due to phase transformation is considered in detail to account for its effects on the temperature field and air flow. As an application of the model, the concentration distribution of the droplet and air relative humidity are calculated under neutral condition. The results of discussion indicate that the range of the dispersion of the spray and the change of the relative humidity is more consistent with the observed than the result without considering the droplet spectrum.