气固系统的底层建模-约简及介尺度结构机理分析

项目名称： 气固系统的底层建模-约简及介尺度结构机理分析

项目编号： No.91434201

项目类型： 重大研究计划

立项/批准年度： 2015

项目学科： 数理科学和化学

项目作者： 张平文

作者单位： 北京大学

项目金额： 300万元

中文摘要： 颗粒流体系统是自然界和工业过程中最普遍的一种现象。探索颗粒流体系统中介尺度行为的形成机理、定量描述和调控机制是过程工业发展的前沿。本项目以流化床反应器中气固两相流系统为主要研究对象，开展可计算建模包括底层建模、模型约简，数值模拟和介尺度结构机理分析等方面研究。底层建模从分子动力学角度出发，使用动理学理论和拟颗粒模型分别构建气固两相Boltzmann方程组和拟颗粒气固两相Boltzmann方程组；模型约简基于对实际问题的认识，使用全局双曲正则化矩方法构造并导出包含实际问题相关的多尺度信息、能描述反应器层次介尺度行为的新型两相流模型；针对各个层次模型特别是新型两相流模型构造高效数值格式，使用高性能计算技术开展数值模拟研究；通过理论分析和数值模拟，研究并揭示反应器层次介尺度行为的结构及其表征、演化规律和稳定性条件，量化介尺度行为对传质、传能影响的规律，并进一步探讨介尺度行为的调控方案。

中文关键词： 气固两相流；Boltzmann方程；可计算建模；介尺度结构；多尺度计算

英文摘要： The particle fluid system is a popular phenomenon in nature and process industry. It is the academic front of the development of process industries, to study the multi-phase reaction processes---the core issue of process industries, and to investigate the formation mechanism, quantitative description and regulatory mechanism of the mesoscale behaviors in these processes. This proposal takes the gas-solid two-phase system in the fluidized bed reactor as the research object, and does research in computable modeling including bottom modeling and model reduction, numerical simulation and mechanism analysis of mesoscale structures. Bottom modeling is based on the molecular dynamics, and using the kinetic theory and pseudo-particle model, to construct the gas-solid two-phase Boltzmann equations and pseudo-particle gas-solid two-phase Boltzmann equations, respectively. Model reduction is based on the knowledge of the practical problem, and using the globally hyperbolic regularized moment method, to build a new two-phase model, which contains the key information of the practical problems, the multi-scale information, and is able to describe the reactor level’s mesocale behaviors. We plan to design efficient numerical schemes for different models especially the new two-phase model, using the high performance computing technology, to do numerical simulation. By theoretical analysis and numerical simulation, we will study and reveal the structure and its characterization, evolution rule and stability conditions of the reactor level’s mesoscale behaviors, and quantify the law of the influence of the mesoscale behaviors on the transformation of mass and energy, and furthermore explore the regulatory mechanism of the mesoscale behaviors.

英文关键词： two phase flow of gas-solid;Boltzmann equation;computable modeling;mesoscale structure;multiscale computing