Numerical Analysis of Fluid Flow and Particle Entrainment in a Novel Tapered Rotating Fluidized Bed
Numerical Analysis of Fluid Flow and Particle Entrainment in a Novel Tapered Rotating Fluidized Bed
复制标题
新型锥形旋转流化床中流体流动和颗粒夹带的数值分析
DOI：
10.1016/j.ces.2014.05.052
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发表时间：
2014
影响因子：
4.7
通讯作者：
Satoru. Watano
中科院分区：
文献类型：
--
作者：
Hideya Nakamura;Naoki Deguchi;Hirohisa Takeuchi;Satoru. Watano
旋转流化床是一种很有前景的用于处理细颗粒的流化技术，属于 Geldart's C 组。然而，显着的颗粒夹带一直是其实际应用的主要障碍。我们在这里提出了一种新型锥形旋转流化床来减少颗粒夹带。锥形旋转流化床的流化床容器具有具有两个截头台端部的圆柱体的几何形状。本文的主要目的是评估锥形旋转流化床在减少颗粒夹带方面的性能。使用计算流体动力学和离散相模型进行计算机模拟，以数值分析当容器几何形状改变时，喷射到干舷的流体流动和粒子运动如何变化。模拟结果表明，通过将容器的几何形状修改为锥形几何形状，朝向出口的径向方向的流体速度显着降低，而切向方向的流体速度增加。模拟结果还表明，夹带颗粒的最大粒径随着锥角的增大而减小：仅通过将容器几何形状改变为锥形几何形状就可以有效地减少颗粒夹带。实验结果表明，使用锥形容器时，夹带颗粒的量显着减少，证实了所提出的锥形旋转流化床可以有效地减少颗粒夹带。
A rotating fluidized bed is a promising fluidization technique for handling of fine particles, classified into the Geldart׳s group-C. However, significant particle entrainment has been a major hurdle for its practical use. We here proposed a novel tapered rotating fluidized bed to reduce the particle entrainment. The fluidized bed vessel of the tapered rotating fluidized bed has the geometry of a cylinder with two frustum ends. The main purpose of this paper is to evaluate a performance of the tapered rotating fluidized bed in reducing the particle entrainment. A computer simulation using a computational fluid dynamics and discrete phase model was conducted to numerically analyze how the fluid flow and particle motion ejected to the freeboard are changed when the vessel geometry is altered. The simulation results revealed that by modifying the geometry of the vessel to the tapered geometry the fluid velocity in the radial direction toward the exit is significantly decreased, while the fluid velocity in the tangential direction is increased. The simulation results also revealed that the maximum particle size of the entrained particles is reduced with an increase in the taper angle: the particle entrainment can be effectively reduced by merely changing the vessel geometry to the tapered geometry. The experimental results showed that amount of entrained particles was significantly decreased when the tapered vessel was used, confirming that the proposed tapered rotating fluidized bed is effective to reduce the particle entrainment.