燃烧产生自由分子区纳米颗粒的团聚-烧结核模型研究

项目名称： 燃烧产生自由分子区纳米颗粒的团聚-烧结核模型研究

项目编号： No.51276077

项目类型： 面上项目

立项/批准年度： 2013

项目学科： 能源与动力工程

项目作者： 赵海波

作者单位： 华中科技大学

项目金额： 80万元

中文摘要： 燃烧源细微颗粒物的生成生长过程涉及复杂颗粒动力学机理，团聚-烧结是控制颗粒物形貌和尺度的最关键机理，其速率(核)模型是对颗粒经历过程进行宏观模拟(如颗粒群平衡模拟)的关键。首先对燃烧环境中自由分子区纳米颗粒碰撞-团聚进行微观模拟，采用不依赖于流体连续性假设的直接模拟Monte Carlo方法描述气相场，考虑布朗扩散和颗粒间相互作用力(如范德华力、静电力等)，研究典型燃烧区域碰撞-团聚机理及核模型；并针对燃烧制备TiO2纳米颗粒过程，实验研究典型烧结主导区、团聚-烧结制约区、团聚主导区的颗粒形貌、表面积、尺度分布等，探究调控颗粒形貌尺度的规律和团聚-烧结竞争机制的物理内涵；最后基于团聚微观模拟和精确实验结果，利用颗粒群平衡模拟反问题方法，辨识团聚-烧结核的不确定模型参数，进行参数不确定度量化和误差传播分析。由此可指导燃烧合成纳米材料的尺度形貌调控和优化，并为燃烧源细微颗粒物的研究提供参考。

中文关键词： 气固两相流；直接模拟Monte Carlo；颗粒群平衡模拟；反问题；团聚-烧结

英文摘要： The formation and growth processes of combustion-generated fine particles are involved in complex particle dynamic mechanisms, among which aggregation and sintering are two of the most critical mechanisms tailoring the morphology and size of particles. As known, the particle aggregation will enlarge particle while lead to irregular morphology, and the particle sintering under high temperature will "smooth" particle surface and conduce restructuring and spheroidization of irregular particles. Thus the competing aggregation-singtering mechanisms determine the surface area, characteristic diamater, internal inhomogeneous structure, and then, the functionality of nanoparticles. It is the key issue for the macroscoic simulation of the dynamic evolution processes (such as population balance modelling) to obtain the kernel models (or occurrence rates) of the two dynamic events. Gas-to-particle synthesis under high temperature is one of the most important methods of nanoparticle synthesis. In order to in-depth understand the inherent mechanisms, this project will first simulate the collision-aggregation process of nanoparticles in the free-molecular regime with respect to typical combustion environment from a mesoscopic view. Accounting for the molecular discontinuity effect from the viewpoint of nanoparticles, the con

英文关键词： gas-solid two-phase flows；Directsimulation Monte Carlo；population balance modeling；inverse problem；aggregation-sintering