气溶胶干沉积速度风洞模拟实验研究

Experimental Study on Aerosol Dry Deposition Velocitiy in Wind Tunnel Simulation

气溶胶是污染物质扩散与传播的重要介质,干沉积是影响气溶胶沉降到地面的重要因素之一。以相似理论为基础,借助中国辐射防护研究院新建环境风洞,对某部分厂址进行了研究,分组开展气溶胶干沉积特征风洞模拟实验,使用粒子动态分析仪(PDA)测量并计算气溶胶粒子的干沉积速度,通过控制变量法对结果分组并进行分析讨论。研究结果表明当控制变量时,在相同的下垫面和风速下,0~2μm和2~5μm的气溶胶粒子的干沉积速度几乎相同,而粒径大于5μm的气溶胶粒子与其有较大差别,重力是影响大粒子干沉积速度的主要因素;当在相同的风速下,与对照试验相比,粒径大于5μm的气溶胶粒子的干沉积速度相较于粒径为0~2μm和2~5μm的气溶胶粒子,所受下垫面地形的影响更加明显,为后续所关注的放射性气溶胶沉积研究积累了基础数据。

Aerosol is an important medium for the diffusion and transmission of pollutants,and dry deposition is one of the important factors affecting the aerosols deposition to the ground.Based on the similarity theory,a newly built environmental wind tunnel by the China Institute for Radiation Protection was used to study some sites.and the wind tunnel simulation experiment of aerosol dry deposition characteristics was carried out in groups.The particle dynamic analyzer(PDA)was used to measure and calculate the dry deposition velocity of aerosol particles,and the results were grouped and analyzed by control variable method.The research results show that when the variables are controlled,under the same underlying surface and wind speed,the dry deposition velocity of aerosol particle sizes of 0~2μm and 2~5μm were almost the same,and aerosol particles with particle sizes greater than 5μm were quite dfferent from them,gravity is the main factor affecting the dry deposition velocity of large particles.Under the same wind speed,compared with the control experiment,the dry deposition velocity of aerosol particles with particle sizes greater than 5μm is more significantly affected by the topography of the underlying surface than aerosol particles with particle sizes of 0~2μm and 2~5μm.This study accumulated basic data for follow-up studies on radioactive aerosol deposition.