A model for turbulent binary breakup of dispersed fluid particles
A model for turbulent binary breakup of dispersed fluid particles
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DOI：
10.1016/s0009-2509(02)00197-5
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发表时间：
2002-08
影响因子：
4.7
通讯作者：
L. Hagesaether;H. Jakobsen;H. Svendsen
中科院分区：
文献类型：
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作者：
L. Hagesaether;H. Jakobsen;H. Svendsen
颗粒尺寸分布的准确预测，以及因此流体颗粒破碎和聚结的基本过程在过程设计中是至关重要的，但是仍然缺乏可靠的方法。本文旨在发展湍流颗粒破碎过程的模块化公式。该模型应包含在一个总体平衡模型中，该模型的制定应便于将来直接实施为一个完整的多流体CFD模型。在不引入可调参数的情况下描述了破碎过程。本模型是Luo和Süssen（AIChE J.42（5）（1996）1225）的现有模型的进一步发展，其已经被扩展和改进，并且其中关于小颗粒和小子颗粒碎片的破碎速率的固有弱点被去除。本文提出了一种新的关于碰撞湍流涡破碎动能密度的判据。这一新判据是描述破碎过程的一个新概念。详细讨论了可能的进一步修改。新模型的结果是令人鼓舞的，因为当分散的流体颗粒的尺寸减小时，破碎率大大降低。此外，对系统变量变化的响应是合理的，并且对于不同的碰撞可能性，子体尺寸的分布以合理的方式变化。
Accurate predictions of particle size distributions, and therefore of the underlying processes of fluid particle breakup and coalescence are of vital importance in process design, but reliable procedures are still lacking. The present paper aims at developing a modular formulation for the turbulent particle breakup process. The model is to be included in a population balance model which is formulated such as to facilitate the direct future implementation into a full multifluid CFD model. The breakup process is described without introducing adjustable parameters. The current model is a further development of an existing model by Luo and Svendsen (AIChE J. 42 (5) (1996) 1225), which has been expanded and refined, and where an inherent weakness regarding the breakup rate for small particles and small daughter particle fragments are removed. A new criterion regarding the kinetic energy density of the colliding turbulent eddy causing breakup has been introduced. This new criterion is a novel concept describing the breakup process. The details are thoroughly discussed together with possible further modifications. The results from the new model are encouraging because the breakup rate is greatly reduced when the dispersed fluid particles are reduced in size. Further, the response to changes in system variables is reasonable and the distribution of daughter sizes vary in a reasonable way for the different collision possibilities.