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类型 基础研究 预答辩日期 2017-12-04
开始(开题)日期 2014-01-24 论文结束日期 2017-11-06
地点 热能所一楼会议室 论文选题来源 973、863项目     论文字数 6.5 (万字)
题目 快速流化床颗粒团絮规律的试验与数值模拟研究
主题词 快速流化床,颗粒团絮,气固流动,数值模拟,MP-PIC
摘要 快速流化床(Fast fluidized bed,FFB)是一种高效的气固反应和传热传质设备,近年来广泛运用在煤加压气化和燃烧、费-托合成(FTS)、氧化铝焙烧及提升管式流化催化裂化等工业过程。国内外学者对快速流化床的基本理论和气固流动特性进行了一系列研究,但对快速流化床内介尺度结构的特性还知之甚少,特别是对Geldart B类颗粒在快速流化床内的流动特性和演化规律掌握不够,使快速流化床设备在方法设计、参数优化等方面存在一定困难。本文基于试验和数值模拟手段,对快速流化床内颗粒团絮规律进行了系统的研究。 本文建立了三维可视化快速流化床系统(H=3m, D=0.1m),系统地揭示了Geldart B类颗粒在快速流化床内的全范围气固流动结构及其转变规律,全面定义和描述快速流化床内的气固流动从低速流态化到高速流态化经历的六种气固流动结构。同时,对上升管内颗粒浓度和气固滑移特性等流动特征(流化风速和循环通量等)随操作参数的变化规律进行研究,并建立了这些流动特性和操作参数之间的内在关联式。此外,采用了图像分析和压力信号分析方法,观察并定义了快速流化床内三种高速流动结构并绘制了典型的流动相图,揭示了流动结构的转变规律,并拟合了三种流动结构的转变速度。 提出了基于图像二值法的团絮识别表征方法,并建立了三维颗粒团絮图像采集和处理系统,识别和定义了四种典型的快速流化床上升管内的颗粒团絮类型,分别描述了这四种颗粒团絮的主要特征(尺寸、速度等)和存在范围,并揭示了不同类型团絮形成、发展、聚并直至破碎的演化规律。同时,研究了操作条件和颗粒性质对颗粒团絮特性的影响,进一步揭示了上升管内颗粒团絮的气固流动特性。 采用多相流网格质点(MP-PIC)法,建立了适用于Geldart B类颗粒三维快速流化床的三维数理模型、模型边界条件和数值求解方法,构建了基于本试验三维快速流化床全循环物理模型。通过对系统网格、计算粒子内的颗粒数、曳力模型和颗粒堆积密度等一系列模型参数进行敏感性分析,提出了适用于Gledart B类颗粒在快速流化床数值计算的最优的模型和模型参数群,成功实现了宽筛分Gledart B类颗粒在上升管、两级旋风分离器、下降管和J型返料阀之间全循环流动。 基于数值模拟,系统的研究了操作参数(流化风速、返料风量和储料量)对快速流化床内气固流动的影响。实现了对三维快速流化床上升管内颗粒团絮三种基本结构的模拟,并对不同类型团絮形成、发展、聚并直至破碎的演化规律进行了模拟研究,揭示了上升管内颗粒团絮的性质(颗粒团絮平均浓度、平均速度)的变化规律。进一步揭示快速流化床内颗粒团絮的气固流动特性,特别是团絮形成、发展、聚并直至破碎的演化规律。
英文题目 EXPERIMENTAL AND MODELING STUDY ON PARTICLE CLUSTER BEHAVIOR IN THE FAST FLUIDIZED BED
英文主题词 Fast fluidized bed,particle cluster,gas-solid flow,numerical simulation,MP-PIC
英文摘要 Fast fluidized bed (FFB) is widely used coal combustion and gasification, fluid catalytic cracking of petroleum, Fischer-Tropsch synthesis in due to its high efficiency in gas-solid reaction, heat and mass transfer. Researchers in and abroad have conducted a series studies on basic theory and basic gas-solid behavior of fast fluidized bed. However, the understanding of mesoscopic scale structure in fast fluidized bed is far from enough, especially for handling Geldart B particles, which may cause difficulty in design and optimization of fast fluidized bed systems. Therefore the cluster flow behavior in fast fluidized bed is studied experimentally and simulative in this paper. Three-dimensional visual fast fluidized bed system was established to reveal the gas-solid flow characteristics by Geldart B particles and the correlation between the gas-solid flow behavior and operating conditions have been analyzed. Six flow patterns were identificated through all the operating conditions, and the criterion and typical flow structure were proposed for these flow patterns. The influences of fluidized air velocity and solid mass flux on solid volume fraction and gas-solid slip characteristics were studied, and the relationship between the flow characteristics and operating conditions were revealed. Moreover, based on the image and pressure analysis, three flow patterns in high speed fluidization system is observed, and the fitting transition velocities for these patterns were developed. Based on the multi-phase particle-in-cell (MP-PIC) methodology, three-dimensional Eulerian–Lagrangian numerical model with boundary conditions and solve method was developed for fast fluidized bed handling Geldart B particles. The influences of some crucial modeling parameters, including grid resolution, number of particles per parcel, the drag force models and the particle close pack volume fraction have been systematically compared and optimized, and the numerical experiment platform for the full-loop three-dimensional fast fluidized bed was established. The effects of operating conditions on flow characteristic in fast fluidized bed were analyzed by numerical simulation method. Moreover, three typical cluster flow patterns in three-dimensional fast fluidized bed riser was captured by simulation method. And the cluster properties, i.e. solid volume fraction and velocity of particle cluster in the riser were studied, further illustrated the flow behavior of particle cluster in the fast fluidized bed.
学术讨论
主办单位时间地点报告人报告主题
Monash University 2017 Monash University, Melbourne 陈岱琳 Modeling study of particle clusters in fast fluidized bed
World Chemical Engineering Council 2017 Barcelona, Spain 陈岱琳 Modeling on the hydrodynamics of full-loop circulating spouted bed
中国工程热物理学会 2014 西安 陈岱琳 快速流化床气固流动结构及其转变的试验研究
东南大学能源与环境学院 2014 南京 陈岱琳 气固流化床颗粒团絮规律的实验和数值模拟研究
东南大学能源与环境学院 2013 南京 陈岱琳 流化床颗粒团絮的研究
东南大学能源与环境学院 2013 南京 于俊崇 世界军用核动力发展趋势
东南大学能源与环境学院 2017 南京 刘超群 DNS Study on Relation between Vorticity and Vortex
东南大学能源与环境学院 2017 南京 陈标华 Selective Transformation of various Nitrogen-containing Exhaust Gases towards N2 over Zeolite Catalysts
     
学术会议
会议名称时间地点本人报告本人报告题目
International Conference on Spouted Beds 2017 Barcelona, Spain Modeling on the hydrodynamics of full-loop circulating spouted bed
2014 年中国工程热物理学会多相流年会 2014 西安 快速流化床气固流动结构及其转变的试验研究
     
代表作
论文名称
Experiments on particle cluster behaviors in a fast fluidized bed
Interactions of spout jets in a multiple-spouted bed
快速流化床气固流动结构及其转变
 
答辩委员会组成信息
姓名职称导师类别工作单位是否主席备注
章名耀 正高 教授 博导 东南大学能源与环境学院
刘德彰 正高 教授 博导 南京航空航天大学能源与动力学院
卢平 正高 教授 博导 南京师范大学能源与机械工程学院 南京师范大学能源与机械工程学院院长
肖睿 正高 教授 博导 东南大学能源与环境学院 东南大学能源与环境学院院长
袁竹林 正高 教授 博导 东南大学能源与环境学院
      
答辩秘书信息
姓名职称工作单位备注
王沛 其他 讲师 东南大学能源与环境学院