燃煤过程亚微米颗粒形成过程的模拟.pdfVIP

第l3卷第6期 燃 烧 科 学 与 技 术 V01．13 No．6 2OO7年l2月 Journalof Col~ oll Science and Technology Dec．2007 燃煤过程亚微米颗粒形成过程的模拟 黎春梅，柳朝晖，郑楚光 (华中科技大学煤燃烧国家重点实验室，武汉430074) 摘 要：燃煤中的亚微米颗粒的形成主要经历成核、冷凝和凝并3个过程．通过对颗粒的分布作出一个合理的对 数正态分布假设，运用矩方法求解颗粒的通用动力学方程，来研究颗粒的尺寸分布情况．数值计算结果表明，对于 不同初始分散性的颗粒，在成核、冷凝和凝并作用下，颗粒的数密度先增大后减小，颗粒的平均体积先减小后增大， 分散性先增大后减小，最终趋于一致的均匀程度．对各单个过程的比较结果显示，凝并的作用最大，成核的作用只 在颗粒形成的初期，冷凝的作用最小． 关键词：亚微米颗粒；成核；冷凝；凝并；矩方法；尺寸分布 中图分类号：TK16 文章标志码：A 文章编号：1006-8740(2007)06-0559．04 Simulation of Formation of Submicron Particles Generated in the Coal Combustion LI Chun—mei，L1U Zhao—hui，ZHENG Chu—guang (State Key Laboratory of Coal Combustion，Huazhong University of Science and Technology，Wuhan 430074，China) Abstract：Generation of submicmn partides in coal combustion process mainly undergo three stages：nucleation、condensation and coagulation．To study the ehanse of particle size distribution，a general dynamic equation is established based on the moment method and the a88uinption ofa reasonable log-normal size distribution．The simulation results show that the number of particles undergoing nucleation、condensation and coagulation，increases inthe early stage and then decreases，thatthe average volume of all particles decreases first and then increases，and that the geometric stglldard deviation increases first and then decreases，reaching a certain steady state in the end．Comparisons of a single process show that coagulation has a most important effect on submicron particle formation nucleation OCCIII~in the early stage of particle formation；condensation has a relatively minor effect on particle