Toward general regime maps for cohesive‐particle flows: Force versus energy‐based descriptions and relevant dimensionless groups
Toward general regime maps for cohesive‐particle flows: Force versus energy‐based descriptions and relevant dimensionless groups
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DOI：
10.1002/aic.17337
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发表时间：
2021-09
期刊：
影响因子：
3.7
通讯作者：
W. LaMarche;Peiyuan Liu;Kevin M. Kellogg;A. Lattanzi;C. Hrenya
中科院分区：
文献类型：
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作者：
W. LaMarche;Peiyuan Liu;Kevin M. Kellogg;A. Lattanzi;C. Hrenya
关于基于力或能量的描述更适合于凝聚粒子相互作用，存在许多混乱。我们假设，当持久接触占主导地位时，基于力的描述是适当的，当接触本质上是短暂的时，基于能量的描述是适当的。具体而言，当持久接触占主导地位时，动量通过力链传递，并且颗粒需要克服凝聚力以引起相对运动，而经历短暂接触的颗粒通过碰撞传递动量，并且必须克服凝聚增强的能量损失以避免团聚。这个假设是通过尝试崩溃的无量纲，因变量表征一个给定的系统对两个无量纲的数字：一个广义的键数，BOG比的最大凝聚力的驱动力流，和一个新的团聚数，Ag比的临界凝聚能的颗粒能量。一系列实验和模拟系统（流化床、料斗等），和内聚源（货车德瓦尔斯、湿度等），考虑了对于持久接触系统，玻碳会发生塌陷，而银不会，对于短暂接触系统，反之亦然，从而为假设提供支持。一个明显的差异与过去的工作得到解决，并收集到新的见解格尔达特的分类。
Much confusion exists on whether force‐ or energy‐based descriptions of cohesive‐particle interactions are more appropriate. We hypothesize a force‐based description is appropriate when enduring‐contacts dominate and an energy‐based description when contacts are brief in nature. Specifically, momentum is transferred through force‐chains when enduring‐contacts dominate and particles need to overcome a cohesive force to induce relative motion, whereas particles experiencing brief contacts transfer momentum through collisions and must overcome cohesion‐enhanced energy losses to avoid agglomeration. This hypothesis is tested via an attempt to collapse the dimensionless, dependent variable characterizing a given system against two dimensionless numbers: A generalized bond number, BoG–ratio of maximum cohesive force to the force driving flow, and a new Agglomerate number, Ag–ratio of critical cohesive energy to the granular energy. A gamut of experimental and simulation systems (fluidized bed, hopper, etc.), and cohesion sources (van der Waals, humidity, etc.), are considered. For enduring‐contact systems, collapse occurs with BoGbut not Ag, and vice versa for brief‐contact systems, thereby providing support for the hypothesis. An apparent discrepancy with past work is resolved, and new insight into Geldart's classification is gleaned.