Chemical Engineering Research and Design ( IF 3.9 ) Pub Date : 2021-08-11 , DOI: 10.1016/j.cherd.2021.07.031 Carmine Sabia 1, 2 , Giovanni Frigerio 3 , Tommaso Casalini 1 , Luca Cornolti 1 , Luca Martinoli 4 , Antonio Buffo 2 , Daniele L. Marchisio 2 , Maurizio C. Barbato 1
In this work we present a method to investigate the fluid-dynamics of a 3D, real-scale spiral jet mill when caking is occurring. CFD simulations are employed to deeply study the pressure and the velocity fields of the gas phase when the nozzles inlet pressure and the chamber diameter are varied to mimic the condition generated by the aggregates formation during the micronizaton process. The computational model is built replicating the experimental observation consisting in the fact that most of the crusts form on the outer wall of the chamber. Simulations underline that caking causes the deterioration of the classification capabilities of the system if the gas mass flow rate is kept constant at nozzles, allowing larger particles for escaping the system. It is shown that it is possible to mitigate this phenomenon by gradually reducing the gas mass-flow rate to keep constant the nozzles absolute pressure. This keeps unchanged the fluid spin ratio and the classification characteristics when caking is advancing.
中文翻译:
受结块现象影响的螺旋气流磨中流动模式和单相速度变化的详细 CFD 分析
在这项工作中,我们提出了一种方法来研究发生结块时 3D 真实比例螺旋气流磨的流体动力学。当喷嘴入口压力和腔室直径变化时,CFD 模拟被用来深入研究气相的压力和速度场,以模拟微粉化过程中聚集体形成所产生的条件。计算模型的建立复制了实验观察,其中大部分结壳形成在腔室的外壁上。模拟强调,如果气体质量流量在喷嘴处保持恒定,则结块会导致系统分类能力下降,从而允许较大的颗粒逸出系统。结果表明,通过逐渐降低气体质量流量以保持喷嘴绝对压力恒定,可以减轻这种现象。这在结块推进时保持流体自旋比和分级特性不变。