Abstract A dynamic, single-path model is developed for dry powder transport in the lungs. The model differentiates between particle behavior in the respiratory bronchioles and alveolar ducts on one hand and inside the alveoli on the other. In particular, it considers the alveolar volume of each generation as a mixing chamber. Air inflow to the alveoli is calculated by accounting for the deformation of airways during breathing. Particle dispersion along the respiratory tract is taken into account and mechanistic deposition rates are developed for the alveoli. Deposition by Brownian diffusion is modeled by a concentration boundary layer, whose thickness varies inversely with the intensity of mixing. The plausibility of the assumption of alveolar mixing is tested indirectly by comparison of model predictions with benchmark data of the exhaled concentration profile and of the pulmonary deposition of continuously inhaled aerosols. The observed agreement lends support to the hypothesis that alveolar mixing represents fundamental physics of the breathing process. It also supports the suggestion that alveolar mixing provides an additional axial dispersion mechanism in the acinus, which is independent of particle size and is active at zero gravity. Copyright © 2020 American Association for Aerosol Research

中文翻译：

---

通过动态单路径模型研究肺泡混合对颗粒滞留和沉积的影响

摘要 开发了一种用于肺部干粉运输的动态单路径模型。该模型一方面区分呼吸性细支气管和肺泡管中的粒子行为，另一方面区分肺泡内的粒子行为。特别是，它将每一代的肺泡体积视为一个混合室。通过考虑呼吸期间气道的变形来计算流入肺泡的空气。考虑了沿呼吸道的颗粒分散，并为肺泡开发了机械沉积率。布朗扩散沉积由浓度边界层建模，其厚度与混合强度成反比。通过将模型预测与呼出浓度曲线和连续吸入气溶胶肺部沉积的基准数据进行比较，间接测试了肺泡混合假设的合理性。观察到的一致性为肺泡混合代表呼吸过程的基本物理学的假设提供了支持。它还支持以下建议，即肺泡混合在腺泡中提供了额外的轴向分散机制，该机制与颗粒大小无关并且在零重力下活跃。版权所有 © 2020 美国气溶胶研究协会 它还支持以下建议，即肺泡混合在腺泡中提供了额外的轴向分散机制，该机制与颗粒大小无关并且在零重力下活跃。版权所有 © 2020 美国气溶胶研究协会 它还支持以下建议，即肺泡混合在腺泡中提供了额外的轴向分散机制，该机制与颗粒大小无关并且在零重力下活跃。版权所有 © 2020 美国气溶胶研究协会