A Numerical Study of Water Loss Rate Distributions in MDCT-Based Human Airway Models.
A Numerical Study of Water Loss Rate Distributions in MDCT-Based Human Airway Models.
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基于MDCT的人类气道模型中水损失率分布的数值研究。
DOI：
10.1007/s10439-015-1318-3
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发表时间：
2015-11
影响因子：
3.8
通讯作者：
Lin CL
中科院分区：
文献类型：
--
作者：
Wu D;Miyawaki S;Tawhai MH;Hoffman EA;Lin CL
应用三维 (3D) 和一维 (1D) 计算流体动力学 (CFD) 方法来研究三种基于多探测器行计算机断层扫描 (MDCT) 的人体气道模型在每分钟通气量为 6、15 和 30 L/min 时的区域失水情况。 3D 和 1D 模型预测的整个呼吸道的总体失水量与现有的实验测量结果一致。然而，由于分叉处形成的3D二次流，3D和1D模型揭示了不同的区域失水率分布。二次流导致吸气时局部温度和湿度分布偏斜，从而提高局部失水率；隆突处的二次气流倾向于将更多的冷空气分配到下叶。因此，3D 模型预测失水率首先随着气道生成的增加而增加，然后随着空气接近饱和而降低，而 1D 模型预测失水率随着气道生成的增加而单调下降。此外，3D（或1D）模型预测下叶（或上叶）的失水率相对较高。区域失水率可以通过无量纲传质系数(h0*)与无量纲壁面剪应力(τ*)相关联，为h0* = 1.15 τ*0.272，R = 0.842。
Both three-dimensional (3D) and one-dimensional (1D) computational fluid dynamics (CFD) methods are applied to study regional water loss in three multi-detector row computed-tomography (MDCT)-based human airway models at the minute ventilations of 6, 15 and 30 L/min. The overall water losses predicted by both 3D and 1D models in the entire respiratory tract agree with available experimental measurements. However, 3D and 1D models reveal different regional water loss rate distributions due to the 3D secondary flows formed at bifurcations. The secondary flows cause local skewed temperature and humidity distributions on inspiration acting to elevate the local water loss rate; and the secondary flow at the carina tends to distribute more cold air to the lower lobes. As a result, the 3D model predicts that the water loss rate first increases with increasing airway generation, and then decreases as the air approaches saturation, while the 1D model predicts a monotonic decrease of water loss rate with increasing airway generation. Moreover, the 3D (or 1D) model predicts relatively higher water loss rates in lower (or upper) lobes. The regional water loss rate can be related to the non-dimensional wall shear stress (τ*) by the non-dimensional mass transfer coefficient (h0*) as h0* = 1.15 τ*0.272, R = 0.842.