AXIAL-DISPERSION IN RESPIRATORY BRONCHIOLES AND ALVEOLAR DUCTS
AXIAL-DISPERSION IN RESPIRATORY BRONCHIOLES AND ALVEOLAR DUCTS
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DOI：
10.1152/jappl.1988.64.6.2614
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发表时间：
1988-06-01
影响因子：
3.3
通讯作者：
FREDBERG, JJ
中科院分区：
文献类型：
--
作者：
FEDERSPIEL, WJ;FREDBERG, JJ
在呼吸性细支气管和肺泡管模型中，通过分析稳定流动期间的轴向气体分散来表征肺腺泡中气体的混合。一个分析（矩量法）开发用于解决在多孔介质中的分散被用来推导出轴向分散系数（D*）的积分表达式。D* 的评估需要求解流场的Navier-Stokes方程和分析中产生的对流扩散型方程。 D* 强烈依赖于肺泡体积/中央导管体积、肺泡与中央导管连通的孔径大小和Peclet数（Pe）。在较小的Pe（流速）下，D* 基本上小于分子扩散系数，而在较大的Pe（流速）下，D* 远大于流动增强分散的Taylor-Aris结果，因为在较小的Pe下，D * 明显大于Taylor-Aris结果所指示的。这些行为超越了以前建立的肺腺泡中气体混合的下限和上限。
The mixing of gases in the pulmonary acinus was characterized by analyzing axial gas dispersion during steady flow in models of respiratory bronchioles and alveolar ducts. An analysis (method of moments) developed for addressing dispersion in porous media was used to derive an integral expression for the axial dispersion coefficient (D*). Evaluation of D* required solving the Navier-Stokes equations for the flow field and a convection-diffusion type equation arising from the analysis. D* was strongly dependent on alveolar volume per central duct volume, the aperture size through which the alveoli communicate with the central duct, and the Peclet number (Pe). At smaller Pe (flow rate) D* was substantially smaller than the molecular diffusion coefficient, whereas at larger Pe (flow rate) D* was much greater than the Taylor-Aris result for flow-enhanced dispersion because appreciable at smaller Pe than indicated by the Taylor-Aris result. These behaviors transcend both the lower and upper limits established previously for gas mixing in the pulmonary acinus.