Orthokinetic Aggregation During Precipitation: A Computational Model for Calcium Oxalate Monohydrate
Orthokinetic Aggregation During Precipitation: A Computational Model for Calcium Oxalate Monohydrate
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DOI：
10.1205/026387697523615
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发表时间：
1997-02
影响因子：
3.9
通讯作者：
H. S. Mumtaz;M. Hounslow;N. Seaton;W. Paterson
中科院分区：
文献类型：
--
作者：
H. S. Mumtaz;M. Hounslow;N. Seaton;W. Paterson
Smoluchowski的理论正交动力学凝聚球扩展到聚集在草酸钙沉淀一水合物。流体力学和沉积在一个二元聚集事件的物理模型相结合，以确定成功的碰撞与不同的方向的剪切场。因此，引入了一个效率项，它代表了导致聚集体的碰撞比例。该模型用于研究剪切速率、晶体尺寸和离子浓度对聚集速率常数β Ag的影响。在剪切速率下观察到β agg的最大值，其对应于两个相反的效应;增加碰撞速率和增加晶体之间的拉伸应力。相比之下，Smoluchowski的理论预测了直接比例。与Smoluchowski理论相比，β agg对晶体尺寸相对不敏感。最后，β agg对溶液离子浓度高度敏感，这是Smoluchowski理论没有考虑的效应。
Smoluchowski's theory for orthokinetic coagulation of spheres is extended to aggregation during precipitation of calcium oxalate monohydrate. Physical models for hydrodynamics and deposition in a binary aggregation event are combined to determine the success of collisions with different orientations to the shear field. Consequently, an effciency terms introduced that represents the proportion of collisions resulting in aggregates. The model is used to investigate the effect of shear rate, crystal size and ion concentration on the aggregation rate constant, β agg . A maximum in β agg is observed with shear rate that corresponds to two opposing effects; increasing rate of collisions and increasing tensile stress between crystals. By contrast Smoluchowski's theory predicts direct proportionality. Compared with Smoluchowski's theory, β agg is relatively insensitive to crystal size. Finally, β agg is highly sensitive to solution ion concentration, an effect Smoluchowski's theory does not consider.