On intra- and intersubject variabilities of airflow in the human lungs
On intra- and intersubject variabilities of airflow in the human lungs
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DOI：
10.1063/1.3247170
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发表时间：
2009-10-01
影响因子：
4.6
通讯作者：
Lin, Ching-Long
中科院分区：
文献类型：
--
作者：
Choi, Jiwoong;Tawhai, Merryn H.;Lin, Ching-Long
通过大涡模拟研究了气道几何形状的个体内和个体间变异对人肺气流的影响。根据 CT 图像重建了两名受试者的气道模型，包括胸外气道和胸内气道。对于受试者内研究，在具有四种不同截断水平的同一受试者的气道几何形状上模拟两种吸气流速下的气流。这些气道模型是原始的完整几何形状以及通过分别在声门下、声门上和喉咽部截断原始几何形状而获得的三种几何形状。完整几何模型中气流的比较表明，无论雷诺数如何，气管中湍流喉射流在平均速度、湍流统计、相干结构和压力分布方面的特征都是相似的。然而，截断气道模型不会产生在完整几何结构中观察到的类似流动结构。然后针对喉咽处截断的气道模型提出改进的入口边界条件，以提高求解的精度。新的边界条件显着改善了平均流量。光谱分析表明，湍流特征是在远离声门的下游捕获的。对于受试者间研究，虽然整体流动特征相似，但发现两个形态因素显着影响受试者之间的流动。这些是声门相对于气管的收缩比率以及气道的曲率和形状。 c 2009 年美国物理研究所。 [doi:10.1063/1.3247170]
The effects of intra- and intersubject variabilities in airway geometry on airflow in the human lungs are investigated by large eddy simulation. The airway models of two human subjects consisting of extra- and intrathoracic airways are reconstructed from CT images. For intrasubject study, airflows at two inspiratory flow rates are simulated on the airway geometries of the same subject with four different levels of truncation. These airway models are the original complete geometry and three geometries obtained by truncating the original one at the subglottis, the supraglottis, and the laryngopharynx, respectively. A comparison of the airflows in the complete geometry model shows that the characteristics of the turbulent laryngeal jet in the trachea are similar regardless of Reynolds number in terms of mean velocities, turbulence statistics, coherent structures, and pressure distribution. The truncated airway models, however, do not produce the similar flow structures observed in the complete geometry. An improved inlet boundary condition is then proposed for the airway model truncated at the laryngopharynx to improve the accuracy of solution. The new boundary condition significantly improves the mean flow. The spectral analysis shows that turbulent characteristics are captured downstream away from the glottis. For intersubject study, although the overall flow characteristics are similar, two morphological factors are found to significantly affect the flows between subjects. These are the constriction ratio of the glottis with respect to the trachea and the curvature and shape of the airways. c 2009 American Institute of Physics. [doi:10.1063/1.3247170]