Abstract In a fluidized bed spray granulation, a particle-particle adhesion by a liquid bridge, which shows dynamic motion due to moving particles, is the most fundamental phenomenon. Therefore, understanding of the particle-particle adhesion by such a dynamic liquid bridge is very important to elucidate mechanisms of particle agglomeration phenomenon in the wet granulation. In this study, the particle-particle adhesion phenomenon at the individual particle scale was analyzed using a direct numerical simulation. Collision of two particles mediated by binder droplets on a particle surface was simulated. In particular, the effect of droplet size under constant total liquid volume on adhesiveness of two colliding particles was investigated. In the present simulation, multiple liquid bridges were simultaneously formed, and these liquid bridges coalesced into single liquid bridge. The simulation results exhibited that the adhesiveness of particles increased with a decrease in the droplet diameter under a constant total liquid volume. In an initial stage of the particle growth in a fluidized bed spray granulation, the tendency of the calculations was consistent with experimental results. We revealed that the capillary pressure force and shapes of the liquid bridge are key factors for particle-particle adhesion at different droplet sizes under constant total liquid volume.

中文翻译：

---

液滴尺寸对碰撞粒子通过液滴的粒子间附着力的影响

摘要 在流化床喷雾造粒中，颗粒与颗粒之间通过液桥粘附，由于颗粒运动而呈现动态运动，是最基本的现象。因此，通过这种动态液桥了解颗粒-颗粒粘附对于阐明湿法制粒中颗粒团聚现象的机制非常重要。在这项研究中，使用直接数值模拟分析了单个粒子尺度上的粒子-粒子粘附现象。模拟由颗粒表面上的粘合剂液滴介导的两个颗粒的碰撞。特别地，研究了在恒定总液体体积下液滴尺寸对两个碰撞粒子的粘附性的影响。在目前的模拟中，同时形成了多个液桥，这些液桥合并成单个液桥。模拟结果表明，在总液体体积不变的情况下，颗粒的粘附性随着液滴直径的减小而增加。在流化床喷雾造粒中颗粒生长的初始阶段，计算趋势与实验结果一致。我们发现毛细管压力和液桥的形状是在恒定总液体体积下不同液滴尺寸下颗粒 - 颗粒粘附的关键因素。计算趋势与实验结果一致。我们发现毛细管压力和液桥的形状是在恒定总液体体积下不同液滴尺寸下颗粒 - 颗粒粘附的关键因素。计算趋势与实验结果一致。我们发现毛细管压力和液桥的形状是在恒定总液体体积下不同液滴尺寸下颗粒 - 颗粒粘附的关键因素。