Abstract Particle size reduction in spiral jet mills is induced by high velocity gas jets, causing interparticle and particle wall collisions leading to breakage. Despite extensive research on the design and operational parameters, the underlying mechanics of size reduction is still poorly understood. Discrete Element Method and Computational Fluid Dynamics are used here to analyse particle and fluid motions. A fast shearing dense particle bed is formed on the wall, with a transition to lean phase towards the centre of the mill. This necessitates four-way coupling of fluid and particle interactions for analysis. It is shown that increasing the depth of the particle bed reduces the fluid phase tangential velocity in the proximity of the classifier, as momentum is exchanged with circulating particles. The energy dissipation through particle collisions occurs mainly along the bed surface and in front of the grinding jet nozzles.

中文翻译：

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滞留量对螺旋气流磨中气体和颗粒流动模式的影响

摘要 螺旋气流磨中的颗粒尺寸减小是由高速气体射流引起的，引起颗粒间和颗粒壁碰撞导致破碎。尽管对设计和操作参数进行了广泛的研究，但对尺寸减小的基本机制仍然知之甚少。这里使用离散元方法和计算流体动力学来分析粒子和流体运动。在壁上形成快速剪切的致密颗粒床，并朝着磨机中心过渡到贫相。这需要流体和粒子相互作用的四向耦合以进行分析。结果表明，随着动量与循环颗粒交换，增加颗粒床的深度会降低分级器附近的流体相切向速度。