下降管反应器内颗粒流动升温过程数值研究  

Numerical study on the flow and heating process of particles in a downer reactor

作　　者：沈新悦 董楠航 SHEN Xinyue;DONG Nanhang(Guangdong Provincial Key Laboratory of New and Renewable Energy Research and Development,Guangzhou 510640,China;School of Energy and Power Engineering,Northeast Electric Power University,Jilin 132012,China)

机构地区：[1]广东省新能源和可再生能源研究开发与应用重点实验室,广东广州510640 [2]东北电力大学能源与动力工程学院,吉林吉林132012

出　　处：《热科学与技术》2020年第2期146-152,共7页Journal of Thermal Science and Technology

基　　金：广东省新能源和可再生能源研究开发与应用重点实验室开放基金资助项目(Y707s51001)。

摘　　要：采用数值模拟的手段研究了下降管反应器内包含不同尺寸及密度冷热颗粒混合物的流动传热特性。双流体模型及离散单元法分别被用于描述颗粒混合物的流动过程并与实验结果进行了对比。反应器内气固相间传热,颗粒混合物间碰撞传热,以及壁面与气/固两相间的热量传递采用计算流体力学和离散单元法相耦合的方式进行了模拟,对颗粒到达反应器出口前影响温度变化趋势的因素展开了分析研究。模拟结果表明:在V型下降管反应器内,粒度较小的颗粒以沿壁面向下滑动为主;较大尺寸颗粒向下流动过程中在反应器截面上分布区域较广;当反应器壁面热边界条件发生变化时,颗粒升温过程变化明显,采用恒温壁面冷颗粒升温速率明显提高;同时热载体颗粒数目越多,冷颗粒在下降管反应器内升温越快。Heat transfer and flow behavior of mixture composed of hot and cold particles with different sizes and densities in a downer reactor is studied numerically. Two-fluid model(TFM) and discrete element method(DEM) have been employed to describe the flow pattern of mixture individually and validated by the experimental data. The heating up of particles has been studied in detail by coupled CFD-DEM considering the heat exchange between gas and solid phases, particle and particle, as well as wall and bed. And the factors that affect the temperature change before the particles reach the reactor outlet.The simulation results indicate that the small particles are mainly sliding down to the outlet of the V-shaped tube reactor while the large particles disperse widely on the cross section of the reactor;the wall of constant temperature is beneficial to the heating up of cold particles together with the increasing number of heat carrier.

关 键 词：升温过程 固体热载体 双流体模型 离散单元法 下降管 

分 类 号：TK6[动力工程及工程热物理—生物能]