ABSTRACT

A major challenge in computational fluid dynamics (CFD) modelling of the human respiratory system is allowing for the variation of geometric scale. A methodology is proposed that enables CFD analysis from the middle through the distal airways to the alveolar level. The methodology relies on a hybrid lung geometry integrating a primary tracheobronchial tree (TBT) up to the fifth generation (section 1) and distal airway (section 2). Section 1 comprises of the middle airways reconstructed from patient CT scans. Section 2 comprises of the distal airway branching tree generated based on deterministic algorithm. The hybrid model allows the application of physiologically relevant boundary conditions in lieu of simplistic approximations used in previous studies. Two different breathing conditions are considered adapted from previous studies, representing resting and exercise activity. The predicted flow variables are assessed for numerical accuracy and validated by comparison with published experimental and numerical data.

摘要

人体呼吸系统计算流体动力学 (CFD) 建模的一个主要挑战是考虑几何尺度的变化。提出了一种方法，可以从中部到远端气道再到肺泡水平进行 CFD 分析。该方法依赖于混合肺几何形状，集成了初级气管支气管树 (TBT) 直至第五代（第 1 部分）和远端气道（第 2 部分）。第 1 部分包括根据患者 CT 扫描重建的中气道。第 2 部分包括基于确定性算法生成的远端气道分支树。混合模型允许应用生理相关的边界条件来代替先前研究中使用的简单近似。两种不同的呼吸条件被认为是根据以前的研究改编的，代表休息和运动活动。评估预测的流量变量的数值准确性，并通过与已发表的实验和数值数据进行比较进行验证。