流固耦合下人体口喉模型气流组织数值仿真研究

Numerical Simulation on Characteristics of Airflow Movement in Human Mouth-throat Model under Effect of Fluid-Solid Coupling

目的:分析人体上呼吸道内流固耦合现象,深入认识上呼吸道内气流运动特性。方法:运用流固耦合力学的方法,对循环呼吸模式下人体口喉模型内气流和呼吸道壁的相互耦合作用进行了数值模拟,分析了流固耦合作用下人体口喉模型内气流组织特性。结果:气流在模型的咽部发生分离现象,并且在咽部和喉部会分别形成2个速度增长点。结论:循环吸气过程中,在声门位置受到几何结构的限制,产生湍流喷射的现象;声门处的喷射致使气流在气管前壁处形成高速气流,气管后方形成流动分离现象;随着与声门距离的增加,气管内、外壁气流速度差逐渐减少。循环呼气过程中,口腔顶部贴近软腭和硬腭部位的气流速度要高于口腔底部,且在口腔顶部发生流动分离现象,形成分离区。该研究结果对于研究气溶胶在人体上呼吸道内的扩散及沉积模式具有重要作用。

Objective To research fluid-solid coupling in human upper respiratory tract so as to deepen understanding of the characteristics of the airflow in human upper respiratory tract and analyze the diffusion and deposition patterns of aerosol in human upper respiratory tract. Methods The fluid solid interaction mechanics was used to simulate fluid-solid coupling in human mouth-throat model in cyclic respiratory pattern, and the airflow movement in human mouth-throat model was analyzed. Results The results showed that the high velocity zone was created in pharynx and larynx, and the phenomenon of airflow separation appeared in the pharynx. The phenomenon of airflow separation didn＇t appear in the pharynx and larynx. Conclusion In the phase of cyclic inhalation, a turbulence jet appears in the glottal region because of the restriction of geometric structure, and the airflow separates in the downstream of the glottis with the separation zone emerging near the poste- rior wall of the upper part of the trachea, and with high velocity zone appearing near the anterior wall. With the increase in the distance with glottis, the velocity difference between the anterior and posterior wall of the trachea gradually decreases. In the phase of cyclic exhalation, the velocity of airflow near the hard palate and soft palate is higher than that on the bottom of mouth, and the phenomenon of airflow separation comes forth on the top.