Abstract Hydrocyclones are used for classification purposes in the mining and mineral processing industries. According to their geometry and under certain operating conditions, hydrocyclones may present roping, which is a defective operation. Studies have related the roping phenomena to many variables such as hydrocyclone geometry and operating conditions. Some authors established a connection between the solids concentration of the feed and the discharge as one of the factors that generate roping. Other authors presented factors such as the apex and the vortex finder diameters, inlet pressure and the relationship between roping generation and the air core. This research aims to study the effect of inlet pressure and particle size distribution in the feed on roping in hydrocyclones. We develop a model using computational fluid dynamics (CFD) in order to study a 75-mm hydrocyclone operating with a variable flowrate and fed with two different materials. Each material is characterized by five granular phases interacting with each other and the model is validated by comparison with experimental data. The turbulence is treated using the Reynolds Stress Model (RSM) and the Eulerian Multiphase Model is used for the interactions between phases. The granular phases are described by the kinetic theory of granular flows (KTGF). The characteristics studied were: (i) air core and material distribution inside the hydrocyclone, (ii) underflow shape and spray angle, (iii) flow and solid concentrations, (iv) efficiency curve and separation size and (v) particle size distribution in the underflow and the cut sizes. According to the results, the particle size distribution of material in the feed has a direct impact on underflow behavior; when operating with coarser material the device tends to rope as the spray angle decreases. The same happens with an increase in the feed pressure. The roping condition generated by the coarse material directly affects the efficiency of the hydrocyclone, triggering an increase in separation size. The underflow particle size distribution tends to be coarser with an increase in the inlet pressure. When the inlet pressure decreases, the overflow particle distribution tends to be finer.

中文翻译：

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进料粒度分布对水力旋流器绕绳的影响

摘要 水力旋流器在采矿和矿物加工业中用于分类目的。根据其几何形状和在某些操作条件下，水力旋流器可能会出现绳索现象，这是一种有缺陷的操作。研究已将绳索现象与许多变量有关，例如水力旋流器几何形状和操作条件。一些作者建立了进料的固体浓度和排放之间的联系，作为产生绳索的因素之一。其他作者提出了诸如顶点和涡流探测器直径、入口压力以及绳索生成与空气核心之间的关系等因素。本研究旨在研究进料中的入口压力和粒度分布对水力旋流器中绳索的影响。我们使用计算流体动力学 (CFD) 开发了一个模型，以研究 75 毫米水力旋流器，该水力旋流器以可变流速运行并以两种不同材料供料。每种材料的特征是五个相互相互作用的颗粒相，并且通过与实验数据的比较来验证模型。湍流使用雷诺应力模型 (RSM) 处理，欧拉多相模型用于相之间的相互作用。颗粒相由颗粒流动力学理论 (KTGF) 描述。研究的特征是：（i）水力旋流器内部的空气核心和材料分布，（ii）底流形状和喷雾角度，（iii）流动和固体浓度，（iv）效率曲线和分离尺寸以及（v）颗粒尺寸分布下溢和切割尺寸。根据结果​​，进料中物料的粒度分布对底流行为有直接影响；当使用较粗的材料时，设备会随着喷雾角度的减小而拉绳。随着进料压力的增加，也会发生同样的情况。粗料产生的成绳状况直接影响水力旋流器的效率，引发分离尺寸的增加。随着入口压力的增加，底流粒度分布趋于更粗。当入口压力降低时，溢流颗粒分布趋于更细。粗料产生的成绳状况直接影响水力旋流器的效率，引发分离尺寸的增加。随着入口压力的增加，底流粒度分布趋于更粗。当入口压力降低时，溢流颗粒分布趋于更细。粗料产生的成绳状况直接影响水力旋流器的效率，引发分离尺寸的增加。随着入口压力的增加，底流粒度分布趋于更粗。当入口压力降低时，溢流颗粒分布趋于更细。