湍流效应对雨滴表面粒子捕集过程的影响  

Influence of turbulent effect on the collection process of aerosols by raindrops

作　　者：华凤皎[1] 亢燕铭[1] 钟珂[1] HUA Feng-jiao;KANG Yan-ming;ZHONG Ke(School of Environmental Science and Engineering, Donghua University, Shanghai 201620, China)

机构地区：[1]东华大学环境科学与工程学院,上海201620

出　　处：《中国环境科学》2017年第1期13-20,共8页China Environmental Science

基　　金：国家自然科学基金资助项目(41275157);上海市教委科研创新重点项目(14ZZ073)

摘　　要：为考察湍流运动对捕集效率的影响,本文在不同湍流强度下分别模拟了4种直径雨滴对不同粒径粒子的捕集过程,根据湍流场中粒子捕集过程的特征,通过引入碰撞概率的概念,重新定义了适用于湍流状态下捕集效率的计算公式,并在此基础上分析研究了湍流捕集效应对捕集效率的影响.结果表明,所有粒径粒子的碰撞概率分布特征都会受到背景湍流强度的影响,尤其对5μm及以下粒子影响明显.湍流捕集效应对捕集效率的影响与粒子密度和粒径直接相关与雨滴尺寸无关.To explore the influence of turbulent motion on collection efficiency,the collecting processes of differentdiameter aerosols captured by four diameter raindrops were estimated by employing numerical simulation with differentturbulent intensities,respectively.Considering the characteristics of scavenging process in the turbulent flow field,theconcept of collision probability was introduced to give the new definition of computational formula of collectionefficiency in turbulent flow condition.On the basis of the concept,the influence of turbulent effect on the collectionefficiency was discussed and analyzed.The numerical results show that the collision probability distributions for particleof different diameters are affected by background turbulent intensity.Furthermore,collection efficiency is stronglyaffected by turbulent intensity for dp≤5μm.The influence of turbulent effect on collection efficiency depends on thedensity and diameter of particle,which was independent of the raindrop diameter.

关 键 词：气溶胶粒子 雨滴 湍流强度 捕集效率 

分 类 号：X513[环境科学与工程—环境工程] P426.6[天文地球—大气科学及气象学]