循环呼吸模式口喉模型内气流运动特性数值模拟
Numerical simulation of airflow movement in human mouth-throat model during cyclic respiratory pattern
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摘要: 应用计算流体动力学方法对人体在循环呼吸模式下口喉模型内的气流运动特性进行数值模拟，分析了循环呼吸模式下口喉模型内的气流组织形式以及气流运动对呼吸道壁面以及气溶胶运动沉积的影响. 吸气阶段，在咽部外壁和声门下游气管上部外壁气流发生分离，形成分离区. 呼气阶段，分别在咽部外壁和喉部外壁形成高速区. 循环呼吸模式下，咽部、喉部与气管内的高轴向速度区和二次涡流运动均是在呼吸过程中间歇性的产生，形成的高剪应力区也是间歇性的. 壁面受到的剪应力周期性地改变方向，引起壁面劳损和组织损伤的可能性增大，同时在这些部位容易造成气溶胶的沉积.Abstract: The method of CFD was used to study airflow movementcharacteristics in human mouth-throat model. We investigated the airflowpatterns in human mouth-throat model, and the effect of airflow movement onthe wall of the mouth-throat model and the aerosols deposition werediscussed. During the inhalation phase, the airflow separates gradually nearthe outer wall of the pharynx and near the outer wall for the upper part ofthe trachea downstream of the glottis with, and the features of theseparation zone appearing is gradually formed. During the exhalation phase,the high velocity zone is created near the outer wall of pharynx and nearthe outer wall of the larynx. During the cyclic respiratory pattern, thehigh axial velocity zone and secondary flow are generated intermittently,eventually to induce the intermittent appearance of the high shearingstrength stress zone appears intermittently. The direction of the shearstress acting on the wall vary varies periodically, which not onlyresult in the increase of the probability of the wall strain and tissueinjury, but also lead to aerosol deposition easily in these areas at thesame time.
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