人体呼吸道内可吸入颗粒径向平面运动的CFD-DEM模拟

CFD-DEM simulation of inhalable particle motion in radial plane of human airway

为分析呼吸道内可吸入颗粒物初始位置与输运特性之间的关系,构建了基于Weibel-23级肺结构的G3～G5级呼吸道模型.采用CFD-DEM方法模拟了球形可吸入颗粒物在呼吸道内的径向平面运动,分析了抛物面型速度进口条件下局部呼吸道的气相场速度分布特点和颗粒物在径向平面内分布位置、速度和颗粒物初始位置之间的关系.研究表明,模型入口中部的颗粒物在G4级壁面附近浓度较高,这是G4级呼吸道壁面产生沉积的原因,入口壁面附近的颗粒物主要分布在G4级中央偏分叉外侧分区;入口中部的颗粒物在G5级外侧分支内呼吸道外侧浓度分布较高,入口壁面附近的颗粒物位于呼吸道中部;入口中部的颗粒物在G5级内侧分支中主要分布于壁面附近和涡的边缘,而入口壁面附近颗粒物仅出现在涡的内部.

In order to investigate the relationship between the initial position and transport characteristics of inhalable particle in airw ay,this paper constructs the generation 3 to 5 airw ay model based on Weibel’s 23 generations pulmonary structure.Computational fluid dynamics-discrete element method（CFD-DEM） is adopted to simulate the radial motions of inhalable spherical particles in the airw ay.The gas phase velocity distribution of local airw ay under parabolic velocity inlet condition and the relationship betw een particle position and velocity in radial plane and its initial position are studied.The results show that the particles in the center of inlet have higher concentration near the boundary leading to the deposition on tube w all in generation 4.The particles near the w all of inlet mainly locate in the tube center tow ards the lateral side in generation 4.The particles in the center of inlet have higher concentration in the lateral side,and the particles near the w all of inlet mostly distribute in the tube center in the lateral branch of generation 5.The particles in the center of inlet generally spread near the boundary and the edge of vortices w hile the particles near the w all of inlet only distribute in the inside of vortices in the inner branch of generation 5.