可溶与不可溶混合PM2．5的蒸汽相变凝结增长  

Growth of Soluble and Insoluble Mixed PM_(2.5) by Vapor Heterogeneous Condensation

作　　者：李林[1,2] 凡凤仙[1,2] 

机构地区：[1]上海理工大学能源与动力工程学院,颗粒与两相流测量研究所,上海200093 [2]上海理工大学上海市动力工程多相流动与传热重点实验室,上海200093

出　　处：《动力工程学报》2015年第7期581-587,604,共8页Journal of Chinese Society of Power Engineering

基　　金：国家自然科学基金资助项目(51206113,51176128);上海市科委科研计划资助项目(13DZ2260900)

摘　　要：建立了蒸汽相变凝结增长的动力学模型,利用数值模拟方法研究可溶与不可溶颗粒组成的混合PM2.5的凝结增长特性,分析了操作参数对相变凝结增长效果的影响.结果表明:PM2.5中可溶颗粒所占比例越大,凝结增长后数目浓度峰值粒径和中位粒径越小,粒径分布越分散;与单一组分的不可溶颗粒相比,可溶颗粒的混入极大地改变了凝结增长后的粒径分布;粒径越小的可溶与不可溶颗粒的凝结增长速率越接近,粒径大于0.3μm时,可溶颗粒的凝结增长速率和最终粒径明显大于不可溶颗粒;较高的初始饱和度和温度能够促进混合PM2.5的凝结增长;随颗粒数目浓度的增大,凝结增长后数目浓度峰值粒径减小,粒径分布更为分散.A dynamic model was established for particle growth by vapor heterogeneous condensation, with which the condensation growth of soluble and insoluble mixed particles was investigated using numerical simulation, so as to analyze the influences of operational parameters on the condensation growth. Results show that the higher the number fraction of soluble particles in the mixed PM2.5 is, the smaller the number concentration peak size and the median size of the droplets will be after condensation growth, resulting in more dispersed distribution of the droplet size. The particle size distribution would be significantly changed after condensation growth when soluble particles are mixed into the insoluble PM2.5. The smaller the parti- cle size is, the closer the condensation growth rate of insoluble particles will be to that of soluble particles. When the particle size is greater than 0.3μm in diameter, the growth rate and final diameter of a soluble particle would be much greater than those of an insoluble particle. The growth rate of the mixed PM2.5 can be promoted by increasing the initial vapor saturation and gas temperature. With the rise of number con- centration of PM2.5, the number concentration peak size decreases after condensation, while the particle size distribution becomes less-dispersed.

关 键 词：凝结增长 动力学模型 PM2.5 粒径分布 可溶颗粒 不可溶颗粒 

分 类 号：X51[环境科学与工程—环境工程]