目的 基于计算流体力学的方法，模拟计算了单个肺泡中的气体与气溶胶颗粒输运情况，研究深层肺泡内气体流动和气溶胶颗粒输运特性。方法 采用一端有周期性扩张/收缩的半球形壁的长直导管作为单一肺泡及肺泡管的简化近似，建立二维数学模拟模型。考虑了呼吸气体在半球边界上的扩散，采用欧拉-欧拉方法对肺泡管中气体以及气溶胶颗粒的输运方程进行求解。结果 整个呼吸过程中，管道中空气的成分比率以稳定的周期方式随时间变化。气溶胶在管道输运主要依赖于颗粒的扩散系数，平流输运只有微小的影响。气溶胶颗粒尺寸减小时，可以观察到气溶胶的扩散速度与深度均有提高，粒径小于4μm时该结论尤为明显，且呼吸频率和幅度的增大可以显著的提升颗粒的输运能力。结论 雾化治疗中，粒径较小的气溶胶颗粒可以增强药物扩散速度。同时深呼吸也有助于提升颗粒的输运效果，治疗中应鼓励患者深呼吸。
Objective The air and aerosol transport in a single alveolus were simulated to study the characteristics of airflow and aerosol transport in deep alveolus based on computational fluid dynamics. Methods A long straight duct with a hemispherical wall at one end which has periodic expansion/contraction were regarded as a simplified approximation of a single alveolus. Based on this, a two-dimensional mathematical model was established. The Euler-Euler method was used to solve the transport equations of airflow and aerosol particles in the alveolus considering the diffusion of air along the boundary of the hemisphere. Results The composition ratio of the air in the duct changes in a stable periodic way during the whole breathing process. The aerosol transport in the duct mainly depends on the particle diffusion coefficient. The advection transport has only a small effect on it. The diffusion velocity and depth of aerosol increased when the particle size decreased, especially when the particle size is less than 4μm. The increase of respiratory frequency and amplitude could significantly improve the transport capacity of aerosol particles. Conclusion In atomization treatment, aerosol particles with smaller particle size have better transportation and curative efficacy. And deep breathing should be encouraged to improve particle transport.