ABSTRACT

Computational Fluid Dynamics is used to model airflow and penetrant behaviour under cough reflex in human airway. The airway geometry segment from the oral cavity to the primary bronchi is reconstructed from CT scan images of a human subject in the standing posture. The inlet flow condition is derived from dynamic cough profiles obtained from two subjects. The mathematical model allows the laryngopharyngeal wall of the airway to remodel. A k-ω turbulence model is used to represent the transitional flow. A Lagrangian approach is used to track solid penetrants in the flow field as a function of penetrant size and density. High velocities are predicted at peak expiratory cough phase. The penetrant size significantly influences the particle residence time and drag force is largely responsible for changes in the penetrant momentum. The smaller penetrants act like tracers in the flow and can escape the airway faster than larger penetrants.

摘要

计算流体动力学用于模拟人气道咳嗽反射下的气流和渗透行为。从口腔到站立支气管的气道几何段是从站立姿势下的人类受试者的CT扫描图像中重建的。入口流量状况是从两个受试者的动态咳嗽曲线中得出的。该数学模型允许气道的喉咽壁重塑。k-ω湍流模型用于表示过渡流。拉格朗日方法用于跟踪流场中的固体渗透剂，该渗透剂是渗透剂尺寸和密度的函数。预计在呼气峰咳嗽高峰期会出现高速。渗透剂的大小会显着影响颗粒的停留时间，而阻力是渗透剂动量变化的主要因素。