Liquid capillary-bridge formation between solid particles has a critical influence on the rheological properties of granular materials and, in particular, on the efficiency of fluidized bed reactors. The available analytical and semi-analytical methods have inherent limitations, and often do not cover important aspects, like the presence of non-axisymmetric bridges. Here, we conduct numerical simulations of the capillary bridge formation between equally and unequally sized solid particles using the lattice Boltzmann method, and provide an assessment of the accuracy of different families of analytical models. We find that some of the models taken into account are shown to perform better than others. However, all of them fail to predict the capillary force for contact angles larger than π/2, where a repulsive capillary force attempts to push the solid particle outward to minimize the surface energy, especially at a small separation distance. We then apply the most suitable model to study the impact of capillary interactions on particle clustering using a coupled lattice Boltzmann and Discrete Element method.

中文翻译：

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固体颗粒之间的毛细管桥力：晶格玻尔兹曼模拟的见解

固体颗粒之间形成的液体毛细管桥对颗粒材料的流变特性，尤其是流化床反应器的效率具有重要影响。可用的解析和半解析方法具有固有的局限性，并且通常不涵盖重要方面，例如非轴对称桥的存在。在这里，我们使用格子 Boltzmann 方法对大小相等和大小不等的固体颗粒之间的毛细管桥形成进行数值模拟，并评估不同系列分析模型的准确性。我们发现所考虑的一些模型表现得比其他模型更好。然而，它们都无法预测大于π 的接触角的毛细管力/2，其中排斥毛细力试图向外推动固体颗粒以最小化表面能，特别是在小的分离距离处。然后，我们应用最合适的模型，使用耦合格子玻尔兹曼和离散元方法研究毛细管相互作用对粒子聚类的影响。