颗粒物在人体上呼吸道模型中沉降规律的数值研究

Numerical Study on the Deposition Characteristics of Particles in a Human Upper Respiratory Tract Model

本文采用RNG k-ε湍流模型对简化的上呼吸道内的流场进行数值仿真,并结合随机涡相互作用模型对上呼吸道内颗粒的局部运动沉积特性进行了数值模拟研究。结果表明,惯性冲击是微米级颗粒物主要的沉降机理,惯性参量能很好地衡量颗粒的沉降规律。口腔中流动较平稳,颗粒受扰动较小。颗粒由于惯性冲击而运动靠近咽部后部并易于沉积在咽部后壁面,咽部的局部沉积分数极大值约为89%。气管内不同截面上轴向速度较大的区域均靠近气管前壁面,且其中的颗粒分布较密集。同时还发现粒径大于10μm的颗粒会更多的沉积在口腔和咽部。此外,从口腔中下部进入的颗粒可以更多的通过气管进入更深的肺部区域。

The flow field of a simplified human upper respiratory tract was simulated by using the RNG k-ε turbulence model.A stochastic eddy interaction model was applied to solve the local movement and deposition characteristics of particles.The results showed that for micrometer-sized particles,the inertial impaction is the main deposition mechanism and the inertial parameter is a good indicator for measuring the deposition of particles.The airflow in oral was smooth and the particles were slightly disturbed.In pharynx region,due to inertial impaction the particles moved close to the rearward of pharynx and were more liable to deposit on the posterior wall of pharynx.The maximum local deposition fraction in pharynx can reach 89%.The region with higher axial velocity was near the anterior wall at cross sections in trachea.In these regions,particles were concentrated.The particles with diameter larger than 10μm can deposit more in oral and pharynx.Furthermore,more fnutions of the particles released from middle and bottom oral can reach the deep lung zones through the trachea.