Bocanegra Evans Humberto, Castillo Luciano
Department of Mechanical Engineering, Texas Tech University, Lubbock, TX 79409, USA.
Department of Mechanical Engineering, Texas Tech University, Lubbock, TX 79409, USA.
J Biomech. 2016 Jun 14;49(9):1601-1606. doi: 10.1016/j.jbiomech.2016.03.043. Epub 2016 Mar 31.
We present a comparison of the flow characteristics in an idealized smooth trachea model and a second model which has a roughness simulating cartilaginous rings. We use refractive index-matched particle image velocimetry (PIV) to measure the velocity field in a two-generation model of the trachea and main bronchi. The flow rate has a trachea-based Reynolds number Re=2800, which is comparable to a resting state. Our results show considerable differences between both cases, the most important of which is the size and magnitude of recirculation zones at the inlet of both bronchi. The smooth case shows a larger separation bubble at the bronchi entrance, which may retain aerosols and have different effects on particles of different sizes. Furthermore, the smooth case displays a higher vorticity along the bottom walls of the bronchi, while a higher vorticity is seen along the trachea walls in the ׳ringed׳ model. These findings suggest that modeling the trachea and main bronchi as smooth tubes may not be justified, since the flow conditions in lower generations will be affected by these differences.
我们对理想化的光滑气管模型和另一个模拟软骨环粗糙度的模型中的流动特性进行了比较。我们使用折射率匹配粒子图像测速技术（PIV）来测量气管和主支气管两代模型中的速度场。流速基于气管的雷诺数Re = 2800，这与静息状态相当。我们的结果显示两种情况之间存在显著差异，其中最重要的是两个支气管入口处回流区的大小和强度。光滑模型在支气管入口处显示出更大的分离泡，这可能会滞留气溶胶并对不同大小的颗粒产生不同影响。此外，光滑模型在支气管底壁沿线显示出更高的涡度，而在“有环”模型中，气管壁沿线的涡度更高。这些发现表明，将气管和主支气管建模为光滑管可能不合理，因为下游代的流动条件会受到这些差异的影响。
