Abstract Fluidisation is a widely used process in the industry as it offers high solid-gas contact efficiency and high heat and mass transfer, hence making it the unit operation of choice for drying. For instance, in the tobacco industry, drying of cut-tobacco is usually performed in fluidised beds. Unlike other particle materials, cut-tobacco exhibit ribbon-like morphology and are highly flexible. The high tendency of such particles to intertwine and form clusters could significantly influence the hydrodynamic characteristics and equipment performance. Therefore, it is of great significance to understand the dynamic behaviours of flexible ribbon particles in the fluidised bed. However, reported studies on such particles in the literature are scarce, and there is no large-scale numerical calculation for that matter. In this paper, the dynamic behaviours of flexible ribbon particles in a fluidised bed are investigated numerically using a two-way coupling of Discrete Element Method (DEM) and Computational fluid dynamics (CFD). A flexible ribbon chain model is used. The spring force constants is proposed and validated reasonably. Compared to other models, the flexible ribbon particle model provides better flexibility. It could also accurately reflect the flow properties of flexible ribbon particles to a certain extent. The effects of particle mass flow rate, superficial gas velocity and other process parameters on the particle dynamics in a fluidised bed are thoroughly studied in this paper. The numerical simulations are validated with experimental data, and the results show a very good agreement.

中文翻译：

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具有柔性带状颗粒的流化床中气固流动的三维模拟

摘要 流化是工业中广泛使用的工艺，因为它具有高固气接触效率和高传热传质，因此使其成为干燥的首选单元操作。例如，在烟草工业中，烟丝的干燥通常在流化床中进行。与其他颗粒材料不同，烟丝呈现出带状形态并且具有高度的柔韧性。这种颗粒相互缠绕并形成团簇的高趋势会显着影响流体动力学特性和设备性能。因此，了解柔性带状颗粒在流化床中的动态行为具有重要意义。然而，文献中对此类粒子的研究报道很少，也没有大规模的数值计算。在本文中，使用离散元方法 (DEM) 和计算流体动力学 (CFD) 的双向耦合，对流化床中柔性带状颗粒的动态行为进行了数值研究。使用灵活的带状链模型。合理地提出并验证了弹簧力常数。与其他模型相比，柔性带状粒子模型提供了更好的灵活性。它还可以在一定程度上准确反映柔性带状颗粒的流动特性。本文深入研究了颗粒质量流速、表观气体速度和其他工艺参数对流化床中颗粒动力学的影响。数值模拟得到了实验数据的验证，结果显示出非常好的一致性。