Evaluation of coarse-grained CFD-DEM models with the validation of PEPT measurements
Evaluation of coarse-grained CFD-DEM models with the validation of PEPT measurements
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DOI：
10.1016/j.partic.2022.12.018
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发表时间：
2023-02-06
期刊：
影响因子：
3.5
通讯作者：
Windows-Yule, Kit
中科院分区：
文献类型：
--
作者：
Che, Hanqiao;Werner, Dominik;Windows-Yule, Kit
计算流体动力学与离散单元法耦合（CFD-DEM）是一种常用的模拟流化床和其他多相系统中气固流动的数值方法。CFD-DEM的一个重要局限性是大量颗粒的真实模拟的可行性。粗粒化（CG）方法，通过该方法，多个单个粒子的组由单个较大的粒子表示，可以在保持相似的系统动力学的同时大大减少粒子的总数。由于这三种CG模型以前没有进行过比较，因此仍然存在一些争论，但是，在CFD-DEM模拟中应用CG的最佳实践。在本文中，我们评估了三个典型的CG方法的性能的基础上模拟鼓泡流化床。这是通过使用数值验证框架来实现的，该框架充分利用高分辨率3D正电子发射粒子跟踪（PEPT）测量来严格验证使用各种不同粗粒化模型和各种不同程度的粗粒化进行的CFD-DEM模拟的输出。从颗粒占有率场、速度场、循环时间、气泡尺寸和速度等方面对颗粒流动行为进行了综合分析。结果表明，CG模拟开始失败时，床室和颗粒之间的尺寸比减小到约20。还观察到，有些令人惊讶的是，应用于颗粒间接触参数的特定CG方法在宽范围的CG因素中对鼓泡床模拟的模拟结果没有实质性影响。(c)2023中国科学院颗粒学会、过程工程研究所。由Elsevier B. V.发布。这是CC BY许可下的开放获取文章（http：//creativecommons.org/licenses/by/4.0/）。
Computational Fluid Dynamics coupled with Discrete Element Method (CFD-DEM) is a commonly used numerical method to model gas-solid flow in fluidised beds and other multiphase systems. A significant limitation of CFD-DEM is the feasibility of the realistic simulation of large numbers of particles. Coarse-graining (CG) approaches, through which groups of multiple individual particles are represented by single, larger particles, can substantially reduce the total number of particles while maintaining similar system dynamics. As these three CG models have not previously been compared, there remains some debate, however, about the best practice in the application of CG in CFD-DEM simulations. In this paper, we evaluate the performance of three typical CG methods based on simulations of a bubbling fluidised bed. This is achieved through the use of a numerical validation framework, which makes full use of the high-resolution 3D positron emission particle tracking (PEPT) measurements to rigorously validate the outputs of CFD-DEM simulations conducted using various different coarse-graining models, and various different degrees of coarse-graining. The particle flow behaviours in terms of the particle occupancy field, velocity field, circulation time, and bubble size and velocity, are comprehensively analysed. It is shown that the CG simulation starts to fail when the size ratio between the bed chamber and the particles decreases to approximately 20. It is also observed, somewhat surprisingly, that the specific CG approach applied to interparticle contact parameters does not have a substantial effect on the simulation results for the bubbling bed simulations across a wide range of CG factors.(c) 2023 Chinese Society of Particuology and Institute of Process Engineering, Chinese Academy of Sciences. Published by Elsevier B.V. This is an open access article under the CC BY license (http:// creativecommons.org/licenses/by/4.0/).