Ligament-type granulation of molten slag in different rotary disk configurations
Ligament-type granulation of molten slag in different rotary disk configurations
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DOI：
10.1016/j.applthermaleng.2017.09.132
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发表时间：
2018-01
影响因子：
6.4
通讯作者：
Hao Peng;Xuekun Shan;X. Ling;Dongxiang Wang;Juan Li
中科院分区：
文献类型：
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作者：
Hao Peng;Xuekun Shan;X. Ling;Dongxiang Wang;Juan Li
旋转圆盘造粒是一种节能、稳定的高温熔渣余热回收方法，其造粒特性决定了生产水泥产品的质量和价值。本文以松香/石蜡混合物为工质，在四种不同的旋转圆盘上进行了模拟实验。采用可视化方法研究了转盘结构对韧带型颗粒特征（韧带数KL、韧带直径dL、毛细管波长λ和液滴平均直径dm）的影响。揭示了液滴脱落过程的机理。结果表明，表面张力决定了韧带和液滴的破碎过程。KL主要受Wen数的影响，而RP混合物体积流量Q、St数和盘结构的影响可以忽略。dL随角速度ω的增大而减小。由于重力的作用，圆弧边圆盘的dL低于平/槽/凸块圆盘的dL。液滴夹断过程的主要模式为短波模式。不同结构的液滴密度预测值大多在测量值的±15%范围内，其中弧边结构的液滴密度最小，推荐使用。因此，KL、dL、λ和d的关联式可适用于各种工况。进一步的研究将集中在液滴特性，以及不同的磁盘配置的最佳设计或选择。
Rotary disk granulation is an energy saving and more stable method for waste heat recovery from high temperature molten slag, and the quality and values of the generated cement product are primary determined by the granulating characteristic. The present work performed the analogue experiments in four types of rotary disks with Rosin/Paraffin mixture as the working fluid. The influence of rotary disk configurations on characteristics of ligament-type granulation, which include ligament numberKL, ligament diameterdL, capillary wavelengthλand droplets mean diameterdmwere investigated through visualized method. Also the mechanism of droplets pitch-off process was revealed. The results indicated that the surface tension forces that determine the most of ligament and droplet breakup processes. TheKLis predominately affected byWenumber, while the influence of RP mixture volume flow rateQ,Stnumber and disk configurations is negligible. ThedLdecreases with the increase in angular speedω. ThedLof arc-edge disk is lower than that of the flat/slotted/bulged-block disks due to the effect of gravity force. The short-wave mode is the dominant mode for droplets pinch-off process. Most of the predicteddmfor different disk configurations are within the band of ±15% of the measured values, and the arc-edge disk configuration is recommended because it can produce the smallest droplets compared with the other types of disks. Accordingly, the correlations forKL,dL, λ anddmare proposed in a wide range of operational conditions. Further investigations will focus on the droplets characteristics, as well as the optimal design or selection of different disk configurations.