Effects of mesh style and grid convergence on particle deposition in bifurcating airway models with comparisons to experimental data
Effects of mesh style and grid convergence on particle deposition in bifurcating airway models with comparisons to experimental data
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DOI：
10.1016/j.medengphy.2006.05.012
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发表时间：
2007-04-01
影响因子：
2.2
通讯作者：
Vinchurkar, Samir
中科院分区：
文献类型：
--
作者：
Longest, P. Worth;Vinchurkar, Samir
许多研究采用了各种各样的网格样式和网格收敛水平来评估分支生物系统模型中的速度场和粒子沉积模式。基于六面体元素生成结构化网格需要大量的时间和精力;然而，这些网格通常与高质量的解决方案相关联。采用四面体单元的非结构化网格可以更快地构建，但可能会增加数值扩散的水平，特别是在具有主要流动方向的管状流动系统中。本研究的目的是更好地建立网格生成技术和网格收敛的影响，速度场和粒子沉积模式的分叉呼吸模型。为了实现这一目标，四个广泛使用的网格样式，包括结构化六面体，非结构化四面体，流动自适应四面体，和混合网格已被认为是两个呼吸气道配置。测试的初始颗粒条件基于入口速度分布或局部入口质量流率。模拟的准确性进行了评估，在文献中的稳态速度场在一个单一的分叉模型，以及在一个双分叉模型的局部颗粒沉积分数的体外实验数据进行比较。基于网格收敛指数（GCI）评估了定量网格收敛，该指数说明了网格细化的程度。对于所考虑的所有分辨率，观察到六面体网格具有比非结构化四面体网格值低一个数量级的GO值。此外，六面体网格样式提供了约1%的GO值，并将运行时间减少了3倍。通过与经验数据的比较，表明进口颗粒沉降应与当地进口质量流量相一致。此外，网格样式被发现有一个可观察到的效果与六面体的解决方案最密切匹配的经验结果的累积颗粒沉积。未来的研究需要评估其他网格生成选项，包括各种形式的混合配置和非结构化六面体网格。(c)2006年IPEM。由爱思唯尔有限公司出版。保留所有权利。
A number of research studies have employed a wide variety of mesh styles and levels of grid convergence to assess velocity fields and particle deposition patterns in models of branching biological systems. Generating structured meshes based on hexahedral elements requires significant time and effort; however, these meshes are often associated with high quality solutions. Unstructured meshes that employ tetrahedral elements can be constructed much faster but may increase levels of numerical diffusion, especially in tubular flow systems with a primary flow direction. The objective of this study is to better establish the effects of mesh generation techniques and grid convergence on velocity fields and particle deposition patterns in bifurcating respiratory models. In order to achieve this objective, four widely used mesh styles including structured hexahedral, unstructured tetrahedral, flow adaptive tetrahedral, and hybrid grids have been considered for two respiratory airway configurations. Initial particle conditions tested are based on the inlet velocity profile or the local inlet mass flow rate. Accuracy of the simulations has been assessed by comparisons to experimental in vitro data available in the literature for the steady-state velocity field in a single bifurcation model as well as the local particle deposition fraction in a double bifurcation model. Quantitative grid convergence was assessed based on a grid convergence index (GCI), which accounts for the degree of grid refinement. The hexahedral mesh was observed to have GO values that were an order of magnitude below the unstructured tetrahedral mesh values for all resolutions considered. Moreover, the hexahedral mesh style provided GO values of approximately 1% and reduced run times by a factor of 3. Based on comparisons to empirical data, it was shown that inlet particle seedings should be consistent with the local inlet mass flow rate. Furthermore, the mesh style was found to have an observable effect on cumulative particle depositions with the hexahedral solution most closely matching empirical results. Future studies are needed to assess other mesh generation options including various forms of the hybrid configuration and unstructured hexahedral meshes. (c) 2006 IPEM. Published by Elsevier Ltd. All rights reserved.