真实人体气管二叉管内吸入颗粒的沉积特性研究

Study on the deposition characteristics of inhaled particle in a real human trachea bifurcation

为研究不同粒径颗粒在气管二叉管内沉积的特性,利用图像辨识技术,直接处理医学CT扫描得到的人体呼吸道原始图像数据,重建得到一个真实人体气管支气管的三维几何模型;采用大涡模拟的方法描述该复杂几何结构内的气体流动,并在拉格朗日框架下跟踪颗粒的运动轨迹.数值计算得到了真实人体气管二叉管内的气体流动速度、压力和颗粒沉积的局部分布.统计了不同呼吸强度(15 L/min和45 L/min)下不同大小(1、5和10μm)的颗粒在不同部位沉积数,结果表明,颗粒在主气管内的沉积占据了重要的地位,模型的几何结构、颗粒的大小、颗粒的重力和呼吸强度等因素综合影响了颗粒的局部沉积效果.

In order to investigate the particle deposition characteristics in the trachea bifurcation, a real three-dimensional geometry of human trachea-bronchi was rebuilt by directly dealing with original CT （computer tomography） scanned respiratory tract images using image recognition technology. Large eddy simulation was used to describe the gas flow in the obtained complex geometry structure and the particles were traced in the Lagrangian frame. The velocity and pressure of airflow, local deposition of particles in the real human trachea bifurcation were computed. The regional particle deposition numbers of different diameters（1,5,10 μm） under different respiratory strength（15 and 45 L/min） were counted. The results indicate that the particle deposition majorly occurs in the trachea. The regional deposition is comprehensively affected by the geometry structure of model, particle diameter, gravity, respiratory strength and so on.