Abstract Industrial waste and brine discharge into nature, has had destructive effects on the environment; solution to which is using Zero Liquid Discharge (ZLD) waste water treatment. Crystallizer as a heart of Zero Liquid Discharge process undertakes creating and growing crystals from the inlet feed solution. Studying the hydrodynamics of the flow assisted by Computational Fluid Dynamics (CFD) is a powerful method of identifying microscopic phenomena in crystallizers. The present paper simulated a common industrial Forced Circulation (FC) crystallizer using the two phase Euler-Euler model, assisted by kinetic theory of granular flow. Turbulence is accounted for by Reynolds Stress Model (RSM), while inter-particle interactions are considered using the Population Balance Model (PBM). Results showed that approximately 65% of the increase in size of crystals happens in the boiling and mixing zone of the crystallizer. Applying the growth rate of 5e-9 [m/s], breakage and aggregation in the crystallizer dominates, contributing 84% of total size increase; while increasing the growth rate and reaching the value of 5e-7 [m/s] results in the growth mechanism surpassing the other mechanisms, contributing 55% of total size increase. Additionally, by 10% increase in particles concentration at the inlet, particles mean diameter at the outlet increases about 6.2%.

中文翻译：

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强制循环结晶器中流体动力学和晶体生长的数值研究

摘要 工业废物和盐水排放到自然界中，对环境产生了破坏性影响；解决方案是使用零液体排放 (ZLD) 废水处理。结晶器作为零液体排放过程的核心，负责从入口进料溶液中产生和生长晶体。在计算流体动力学 (CFD) 的辅助下研究流动的流体动力学是识别结晶器中微观现象的有效方法。本文在颗粒流动力学理论的辅助下，使用两相欧拉-欧拉模型模拟了一个常见的工业强制循环 (FC) 结晶器。湍流由雷诺应力模型 (RSM) 解释，而粒子间相互作用则使用种群平衡模型 (PBM) 来考虑。结果表明，大约 65% 的晶体尺寸增加发生在结晶器的沸腾和混合区。应用5e-9[m/s]的生长速率，结晶器中的破碎和聚集占主导，占总尺寸增加的84%；同时增加生长速度并达到 5e-7 [m/s] 的值导致生长机制超过其他机制，占总尺寸增加的 55%。此外，入口处颗粒浓度每增加 10%，出口处的颗粒平均直径增加约 6.2%。同时增加生长速度并达到 5e-7 [m/s] 的值导致生长机制超过其他机制，占总尺寸增加的 55%。此外，入口处颗粒浓度每增加 10%，出口处的颗粒平均直径增加约 6.2%。同时增加生长速度并达到 5e-7 [m/s] 的值导致生长机制超过其他机制，占总尺寸增加的 55%。此外，入口处颗粒浓度每增加 10%，出口处的颗粒平均直径增加约 6.2%。