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研究上呼吸道内压力和剪应力的循环变动形式,深入认识上呼吸道内气流运动特性,为分析气溶胶在人体上呼吸道内的扩散、转捩以及沉积模式提供科学依据。应用大涡模拟的方法,对人体在低强度呼吸条件下上呼吸道内压力和剪应力进行数值仿真研究,讨论人体口喉模型以及气管支气管内压力和剪应力的分布规律。结果表明:上呼吸道模型内压力梯度变化主要集中在会厌下缘至气管处,压力的最小值在吸气中间时刻,约为呼气中间时刻的2倍,且均位于声门后壁处,气管及其分岔处压力梯度变化明显;剪应力变化随气流速度的变化而变化,方向随呼吸循环发生周期性改变。
To study the cyclic changes of pressure and shear stress in the upper respiratory tract, to understand the characteristics of airflow in the upper respiratory tract and to provide a scientific basis for the analysis of aerosol diffusion, swirling and deposition patterns in the upper respiratory tract. By using the method of large eddy simulation, the numerical simulation of the upper airway pressure and shear stress in the human body under low-intensity respiration was conducted. The distribution of the human throat model and the pressure and shear stress in the trachea and bronchus were discussed. The results showed that the changes of pressure gradient in the upper respiratory tract mainly concentrated on the inferior epiglottis to the trachea, and the minimum pressure was about twice as long as the middle of the inspiratory time, both at the posterior wall of the glottis. The trachea And the pressure gradient at the bifurcation changes obviously. The change of shear stress changes with the change of air velocity, and the direction changes cyclically with the breathing cycle.