Numerical investigation of the three-dimensional flow in a human lung model
Numerical investigation of the three-dimensional flow in a human lung model
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DOI：
10.1016/j.jbiomech.2008.05.016
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发表时间：
2008-08-07
影响因子：
2.4
通讯作者：
Schroeder, Wolfgang
中科院分区：
文献类型：
--
作者：
Freitas, Rainhill K.;Schroeder, Wolfgang
本文对人体上呼吸道从气管到第六代支气管树的吸气和呼气时的流场进行了数值模拟。通过格子Boltzmann方法（LBM）计算了基于水力直径的雷诺数Re-D = 1250的三维定常流。粒子图像测速（PIV）测量的基础上的实验数据验证了模拟。数值模拟和实验结果之间的良好协议证明了通过比较速度轮廓和分布在一个定义的参考平面。结果表明，LBM是一个准确的工具，数值预测在人体肺部的流动结构。使用自动笛卡尔网格生成器，从网格划分到稳态解的总处理时间< 12 h。此外，数值模拟允许更密切的二次流结构的分析比在实验研究。三维流线型模式揭示了一些见解的空气交换机制在吸气和呼气。吸气时，较慢的近壁气管气流通过右主支气管进入右上叶支气管。气管中的体积质量流量几乎均匀地分布在左上、中心和下叶支气管以及右中心和下叶支气管上。在呼气时，来自右上叶支气管的空气进入气管的右中心，并取代来自右下支气管和右中心支气管的气流，使得在吸气和呼气时流线的气管位置被切换。左支气管的血流没有显示出这种转换。研究结果强调了肺几何形状的不对称性对呼吸换气机制的影响。(c)2008爱思唯尔有限公司保留所有权利。
The flow field at inspiration and expiration in the upper human airways consisting of the trachea down to the sixth generation of the bronchial tree is numerically simulated. The three-dimensional steady flow at a hydraulic diameter-based Reynolds number Re-D = 1250 is computed via a lattice-Boltzmann method (LBM). The simulation is validated by the experimental data based on particle-image velocimetry (PIV) measurements. The good agreement between numerical and experimental results is evidenced by comparing velocity contours and distributions in a defined reference plane. The results Show the LBM to be an accurate tool to numerically predict flow structures in the human lung. Using an automatic Cartesian grid generator, the overall process time from meshing to a steady-state solution is < 12 h. Moreover, the numerical simulation allows a closer analysis of the secondary flow structures than in the experimental investigation. The three-dimensional streamline patterns reveal some insight on the air exchange mechanism at inspiration and expiration. At inspiration, the slower near-wall tracheal flow enters through the right principal bronchus into the right upper lobar bronchus. The bulk mass flux in the trachea is nearly evenly distributed over the left upper, center and lower lobar bronchi and the right center and lower bronchi. At expiration, the air from the right upper lobar bronchus enters the right center of the trachea and displaces the airflow from the lower and center right bronchi Such that the tracheal positions of the streamlines at inspiration and expiration are switched. The flow in the left bronchi does not show this kind of switching. The findings emphasize the impact of the asymmetry of the lung geometry on the respiratory air exchange mechanism. (c) 2008 Elsevier Ltd. All rights reserved.