摘要
颗粒系统在实际工业生产及日常生活等各个领域有着非常广泛的应用,而大多数情况下颗粒系统中通常存在一定量的液体,例如喷雾造粒、湿法除尘等过程。其中液体的存在对不同工业过程生产效率起到抑制或促进的作用。因此,如何合理控制颗粒系统中液体含量对提高工业生产效率、优化反应器设计有着不可忽视的作用。本文基于湿颗粒离散软球碰撞模型,并引入传热传质模型,数值模拟研究鼓泡流化床内湿颗粒系统中的传热传质过程,对比鼓泡流化床内不同时刻颗粒速度分布、努塞尔数分布等。研究发现,在干燥初始阶段,不同床层高度处,颗粒速度在0m/s附近,速度分布不对称,说明在此阶段颗粒未充分流化,颗粒在流化床内运动不稳定,受到液体作用的影响较为明显。随着干燥过程的进行,液体量逐渐减小,颗粒速度呈轴对称分布,说明颗粒逐渐被充分流化并获得更大的运动速度。
The particle system has been widely applied in actual industrial production and daily life. Moreover, the existence of a certain amount of liquid in the particle system is an inevitable phenomenon. Therefore, controlling the liquid content in the particle system plays an important role. In this paper, based on the wet particle discrete element method with the heat and mass transfer model introduced, the heat and mass transfer process of wet particle system are investigated in the bubbling fluidized bed. Time-averaged particle velocity, Nusselt number and different heat transfer pathways are analyzed. In the initial stage of drying, at different bed heights, the particle velocity was around 0 m/s, and the velocity distribution was asymmetrical, indicating that the particles were not fully fluidized at this stage. In this stage, particles moved unstable in the fluidized bed under strong effect of liquid. As the drying process progresses, the amount of liquid decreases gradually, and the particle velocity was axisymmetrically distributed, indicating that the particles are gradually fully fluidized and obtain a larger moving speed.
作者
唐天琪
夏靖达
孙珊珊
王铭浩
何玉荣
TANG Tianqi;XIA Jingda;SUN Shanshan;WANG Minghao;HE Yurong(School of Energy Science and Engineering,Harbin Institute of Technology,Harbin 150001,China;Heilongjiang Key Laboratory of New Energy Storage Materials and Processes,Harbin 150001,China)
出处
《工程热物理学报》
EI
CAS
CSCD
北大核心
2022年第11期3011-3019,共9页
Journal of Engineering Thermophysics
基金
国家自然科学基金面上项目(No.52076059)。
关键词
鼓泡流化床
湿颗粒
传热传质特性
离散单元模型
bubbling fluidized bed
wet particle
heat and mass transfer characteristics
discrete element method
