Revisiting and improving models for the breakup of compact dry powder agglomerates in turbulent flows within Eulerian–Lagrangian simulations
Revisiting and improving models for the breakup of compact dry powder agglomerates in turbulent flows within Eulerian–Lagrangian simulations
复制标题
重新审视和改进欧拉-拉格朗日模拟中湍流中致密干粉团块破碎的模型
DOI：
10.1016/j.powtec.2019.03.009
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发表时间：
2019
影响因子：
5.2
通讯作者：
Khalifa
中科院分区：
文献类型：
--
作者：
Breuer;Khalifa
本文研究湍流中团聚体的破碎模型。首先，提供了一个简短的文献综述，描述了关于团聚体破碎的描述和建模的最新技术，特别强调了流体力的作用。这包括湍流和阻力（惯性）应力。此外，破碎的旋转应力被考虑在内。基于使用欧拉-拉格朗日方法依赖于大涡模拟方法的第一原理来描述这些过程的想法，从文献中的建模思想进行了重新审视和扩展，以便应用于四路耦合模拟。基于确定性碰撞和团聚模型，以类似的方式处理破碎过程，从而产生高效的过程，该过程允许跟踪大量的团聚体和颗粒，但限于压实干粉团聚体。对于这种团聚体的强度的增强的评价是依赖于平均孔隙率和配位数的改进的测定。此外，特别强调分手后的处理，即，生成的碎片的大小和速度的模型。最后，将所提出的模型应用于Weiler [1]对干粉分散器中的解聚实验研究的启发下的测试用例。不同的物理机制（湍流，阻力，旋转）的效果进行了分析，破碎率和由此产生的尺寸分布。此外，主要的破碎区域分别确定。由于附聚过程同时考虑，碎片的再附聚被发现发挥不可忽视的作用。最后，研究了粉末的性质对破碎和再团聚过程的影响。
The present study is concerned with breakup models for agglomerates in turbulent flows. First, a brief literature review is provided describing the state of the art concerning the description and modeling of breakup of agglomerates with special emphasis on the role of fluid forces. That comprises turbulent and drag (inertia) stresses. Furthermore, the breakup by rotary stresses is taken into account. Based on the idea to describe these processes using first principles within an Eulerian–Lagrangian approach relying on the large-eddy simulation methodology, modeling ideas from the literature are revisited and extended in order to be applied in a four-way coupled simulation. Building on a deterministic collision and agglomeration model, the breakup process is tackled in a similar manner leading to a highly efficient procedure, which allows to track a huge number of agglomerates and particles but with the restriction to compact dry powder agglomerates. For this kind of agglomerates an enhanced evaluation of the strength is derived relying on an improved determination of the average porosities and coordination number. Furthermore, special emphasis is put on the post-breakup treatment, i.e., models for the sizes and velocities of the generated fragments. Finally, the proposed models are applied to a test case inspired by the experimental study of Weiler [1] for the deagglomeration in a dry powder disperser. The effect of the different physical mechanisms (turbulence, drag, rotation) is analyzed concerning breakup rates and resulting size distributions. Furthermore, the dominant breakup regions are identified separately. Since agglomeration processes are simultaneously taken into account, re-agglomeration of the fragments is found to play a non negligible role. Finally, the effect of the properties of the powder on the breakup and re-agglomeration processes is investigated.
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DOI：
10.1007/s10494-012-9398-8
发表时间：
2012-05
期刊：
Flow, Turbulence and Combustion
影响因子：
--
作者：
Y. Ammar;A. Dehbi;M. Reeks
通讯作者：
Y. Ammar;A. Dehbi;M. Reeks
使用同步高速视频和热膜测量来表征湍流明渠流中的近床相干结构
DOI：
--
发表时间：
1995
期刊：
影响因子：
--
作者：
M. Garcia;F. López;Y. Niño
通讯作者：
Y. Niño
韧性骨料的湍流破碎。
DOI：
--
发表时间：
2015
期刊：
Physical review. E, Statistical, nonlinear, and soft matter physics
影响因子：
--
作者：
C. Marchioli;A. Soldati
通讯作者：
A. Soldati
DOI：
10.1145/1874391.187410
发表时间：
1987-02
期刊：
ACM SIGSOFT Softw. Eng. Notes
影响因子：
--
作者：
Will Tribbey
通讯作者：
Will Tribbey
DOI：
--
发表时间：
2007
期刊：
影响因子：
--
作者：
S. Harada;R. Tanaka;H. Nogami;M. Sawada;K. Asakura
通讯作者：
K. Asakura