Understanding flow distributions in human lungs has attracted significant attention since the last few decades. However, there are still large discrepancies between different studies in the distribution of air flow into alveoli at different generations of bifurcation. In this study, a new method has been developed to calculate expansion ratio of alveoli and ratio of alveolar to ductal flow rate at different generations for air- and saline-filled lungs. The effects of alveolar number, breathing period, lung tidal volume, and surface tension are examined. It is found that the expansion ratio of alveoli varies significantly at different generations in the saline-filled lungs. For the air-filled lung, the expansion ratio of individual alveolus remains constant for different generations. The current study provides new data on the flow rate ratios which is critical for understanding flow distributions and flow behaviors in alveoli. Surface tension in alveoli and alveolar number has obvious effects on the value of flow ratio. The current study sheds new light into the flow behavior in lungs and lays the foundation for detailed study on flow and particle transport characteristics in human lungs.

自从过去的几十年以来，了解人肺中的流量分布已经引起了广泛的关注。但是，在不同的分叉年代，进入肺泡的气流分布的不同研究之间仍然存在很大差异。在这项研究中，已开发出一种新方法来计算充气和充满盐水的肺在不同世代的肺泡膨胀率和肺泡与导管流速的比率。检查肺泡数目，呼吸时间，肺潮气量和表面张力的影响。发现在充满生理盐水的肺中，肺泡的膨胀率在不同世代有显着变化。对于充满空气的肺，不同世代的单个肺泡的膨胀率保持恒定。当前的研究提供了有关流速比的新数据，这对于了解肺泡中的流量分布和流动行为至关重要。肺泡表面张力和肺泡数目对流量比值有明显影响。当前的研究为肺部的流动行为提供了新的思路，并为详细研究人体肺部的流动和颗粒传输特性奠定了基础。