燃煤过程亚微米颗粒形成过程的模拟  

Simulation of Formation of Submicron Particles Generated in the Coal Combustion

作　　者：黎春梅[1] 柳朝晖[1] 郑楚光[1] 

机构地区：[1]华中科技大学煤燃烧国家重点实验室,武汉430074

出　　处：《燃烧科学与技术》2007年第6期559-562,共4页Journal of Combustion Science and Technology

基　　金：国家重点基础研究发展计划(973)资助项目(2002CB211600)

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.Generation of submicron partides in coal combustion process mainly undergo three stages： nucleation,condensation and coagulation. To study the change of particle size distribution, a general dynamic equation is established based on the moment method and the assumption of a reasonable log-normal size distribution. The simulation results show that the number of particles undergoing nucleation,condensation and coagulation,increases in the early stage and then decreases, that the average volume of all particles decreases first and then increases, and that the geometric standard 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 occurs in the early stage of particle formation; condensation has a relatively minor effect on particle formation.

关 键 词：亚微米颗粒 成核 冷凝 凝并 矩方法 尺寸分布 

分 类 号：TK16[动力工程及工程热物理—热能工程]