By CFD-DEM simulations, the present work is aimed to investigate the transient gas-solid bubbling mechanisms along a whole bubble lifecycle in a 2D fluidized bed from a micro perspective. Systemic comparisons with CCD measurements confirm the validity of current simulations. Afterward, the manner of particle motion and its driving mechanisms at various stages are investigated. In order to do that, external forces are analyzed at an individual particle level, including the drag, pressure gradient force, and their resultant acceleration together with gravity. Many interesting findings have been achieved. For example, a switch in directions of drag and pressure gradient forces at the root of an initial bubble enables its detachment. And, regarding their contributions to the burst of a bubble, the drag force is several times of the pressure gradient forces. Present efforts help to offer a novel view of particle dynamics during the bubbling fluidization.

中文翻译：

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D组粒子二维流化床微泡机理的研究

通过 CFD-DEM 模拟，本工作旨在从微观角度研究二维流化床中整个气泡生命周期中的瞬态气固起泡机制。与 CCD 测量的系统比较证实了当前模拟的有效性。随后，研究了不同阶段的质点运动方式及其驱动机制。为了做到这一点，在单个粒子水平上分析外力，包括阻力、压力梯度力，以及它们与重力的合成加速度。已经取得了许多有趣的发现。例如，在初始气泡的根部改变阻力和压力梯度力的方向可以使其脱离。而且，关于他们对泡沫破灭的贡献，阻力是压力梯度力的几倍。目前的努力有助于在鼓泡流化过程中提供粒子动力学的新观点。