Abstract The computational fluid dynamic combining the discrete element method (CFD-DEM) is widely used to comprehend the mechanism of gas–solid flow. However, as a Lagrangian method, DEM suffers from the huge cost for tracking each particle in the systems when applied to industrial applications with billions of fine particles, regardless of the great advances in computing capacity of computers. To address this issue, a coarse-grain (CG) model is proposed in this paper, where the original fine particles are represented by a small number of large-sized CG particles. In the current study, the new-developed CG model combining CFD-DEM (CG CFD-DEM) is applied to investigate the fluidized bed with an immersed tube. The applicability and accuracy of the proposed CG CFD-DEM are validated by the good agreement of the macroscopic behaviors predicted by simulations and those obtained from experiments. For the first time, the CG CFD-DEM is used to predict the erosion around the tube based on the shear impact energy model (SIEM), and the computational results calculated by CG CFD-DEM and original CFD-DEM agree well, which demonstrates that the proposed model can predict the erosion of the tube in the fluidized bed accurately and efficiently. Besides, as expected, the calculation time is drastically reduced due to the CG model, which makes the simulations of large-scale industrial applications accessible.

中文翻译：

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使用粗粒模型对带浸​​管的流化床进行 CFD-DEM 模拟

摘要 结合离散元法的计算流体动力学（CFD-DEM）被广泛用于理解气固流动的机理。然而，作为一种拉格朗日方法，DEM 在应用于具有数十亿细颗粒的工业应用时，跟踪系统中每个颗粒的成本巨大，而不管计算机计算能力的巨大进步。为了解决这个问题，本文提出了一种粗粒（CG）模型，其中原始细颗粒由少量大尺寸的 CG 颗粒表示。在目前的研究中，新开发的结合 CFD-DEM 的 CG 模型（CG CFD-DEM）用于研究浸管流化床。所提出的 CG CFD-DEM 的适用性和准确性通过模拟预测的宏观行为与实验获得的宏观行为的良好一致性得到验证。首次使用CG CFD-DEM基于剪切冲击能量模型(SIEM)预测管周冲蚀，CG CFD-DEM计算结果与原始CFD-DEM计算结果吻合较好，说明表明所提出的模型可以准确有效地预测流化床中管道的侵蚀。此外，正如预期的那样，由于 CG 模型，计算时间大大减少，这使得大规模工业应用的模拟变得容易。CG CFD-DEM基于剪切冲击能量模型（SIEM）用于预测管子周围的侵蚀，CG CFD-DEM计算结果与原始CFD-DEM计算结果吻合较好，表明该模型能够准确有效地预测流化床中管道的侵蚀。此外，正如预期的那样，由于 CG 模型，计算时间大大减少，这使得大规模工业应用的模拟变得容易。CG CFD-DEM基于剪切冲击能量模型（SIEM）用于预测管子周围的侵蚀，CG CFD-DEM计算结果与原始CFD-DEM计算结果吻合较好，表明该模型能够准确有效地预测流化床中管道的侵蚀。此外，正如预期的那样，由于 CG 模型，计算时间大大减少，这使得大规模工业应用的模拟变得容易。