交互双循环流化床的颗粒循环特性与耦合协调机制

The complex dense gas-solid flow is considered as one of the most important fundamental problems of the researches on engineering thermo physics and energy application area. This proposal is based on the novel energy conversion technology “interactive dual circulating fluidized bed”, where a scientific problem of “interactive dual circulating characteristics and coupling coordination mechanism of particles” is proposed and a large number of detailed experimental investigations and numerical simulations will be carry out. The target of this project is try to describe the interactive dual circulating characteristics of particles within each basic unit and between basic units, as well as the coupling coordinated mechanisms and the oriented regulate methods. Besides, it can also enrich the foundational theory system of gas-solid flow researches and provide some theoretical references for the applications of dual fluidized bed. Furthermore, a series of innovative experimental methods, such as x-ray imaging measure of particle concentration, magnetic induction measure of particle residence time and microwave measure of solid flux; as well as innovative numerical simulations such as three-dimensional Euler-Lagrange approach base on MP-PIC. The proposed investigation methods also enrich the technologies of gas-solid flow study including the dual circulating fluidized bed. In general, the research foundational of this proposal is well prepared, and the preliminary researches had also gained remarkable progress, a series of innovative findings would be achieved after this study.

复杂稠密气固流动是工程热物理与能源利用领域的重要基础研究内容，对于反应器设计、结构优化和运行调控都具有重要的学术价值和工程指导意义。本项目针对“交互双循环流化床”能源热转化新工艺提出，围绕科学问题“颗粒的交互循环特性与耦合协调机制”，通过开展大量细致、深入的实验和数值模拟研究工作，较系统阐明循环流化床基本单元内/单元间的颗粒交互循环运动特性、耦合协调机制与定向调控方法，充实气固两相流的基础理论体系，为双流化床的应用提供理论参考；同时尝试/发展一些具有创新性的实验（如X光成像颗粒浓度测量、磁感应颗粒停留时间测量、微波固体通量测量）和数值模拟方法（基于MP-PIC的三维欧拉-拉格朗日数值模拟），丰富双流化床等稠密气固两相流的研究手段。项目具有较好的研究基础，前期研究取得重要进展，可望获得预期创新研究成果。

复杂稠密气固流动是工程热物理与能源利用领域的重要基础研究内容，对于反应器设计、结构优化和运行调控都具有重要的学术价值和工程指导意义。本项目针对“交互双循环流化床”能源热转化新工艺提出，围绕科学问题“颗粒的交互循环特性与耦合协调机制”，通过开展大量细致、深入的实验和数值模拟研究工作。.构建了交互双循环流化床的气固流动试验系统，研究了双循环流化床内/间的交互循环运动特性。在实验的基础上建立了交互循环流化床的三维数理模型，并通过数值试验揭示了实验手段难以获得的颗粒运动特性。通过数值模拟和实验研究，研究了双循环流化床的耦合协调机制并提出了定向调控颗粒运动的方法。.取得的创新性成果如下：..实验研究方面，构建对称型交互循环双流化床冷态试验平台，并在此基础上发展一种基于微波衰减原理和多普勒效应的动态颗粒质量流量测量系统。通过对称工况和非对称工况下的试验研究获取了操作参数对基本流化床单元内床层压降以及上升管颗粒浓度分布的影响规律，并获取了基本流化床单元内气固流动结构的转变规律。应用微波固体质量流量测量方法研究了交互循环双流化床基本流化床单元间的颗粒循环特性。通过处理时序压差数据分析了流化床单元上升管内的全高度颗粒浓度波动特性，揭示了各操作参数对双流化床反应器内动态颗粒浓度波动强度及运行稳定性的影响规律。通过对时序颗粒质量流量标准差及变异系数的分析，揭示了交互循环双流化床流化床单元间连续颗粒循环的波动强度及循环稳定性随操作参数的变化规律。..数值模拟方面，首次构建了基于欧拉-欧拉方法和欧拉-拉格朗日方法的双循环流化床的三维数理模型，并考虑到不同颗粒粒径对于颗粒运动的影响，证明MP-PIC方法适用于研究双循环流化床的颗粒交互循环运动特性。实现了三维维度上的双流化床全场气固流动数值模拟，在此基础上对流动结构、颗粒分布、速度分布等重要流体动力学特性以及双流化耦合运行失稳机理等试验中难以观测的气固流动特性开展了研究。