This study analyzed aspiration and deposition of generated droplets from a single-cough event of an infected person in the airway of a receptor person. For this purpose, two humanoid mannequins in the face-to-face orientation at a distance of 0.5 m from each other inside the quiescent air condition were considered. The healthy receptor person's airway extended from the nostril to the end of 4 lung generation was included in the simulation. The realistic cyclic breathing of the receptor mannequin was also simulated. It was assumed that the infected person's coughing event occurred at the exhalation of the receptor person's breathing. The Ansys-Fluent software was used for all simulations, and the SST turbulence model was employed to simulate the cough, the inhalation, and the surrounding airflow fields. The cough droplet motions were simulated using the Lagrangian particle trajectory analysis approach. User-defined functions for an improved DRW model were developed and implemented into the Ansys-Fluent software. Airflow field simulation results showed that the coughing jet flow led to the formation of vortices near the coughing mannequin. Vortices form and evolve in time during the transient cough jet flow. Also, the coughing event generates a cloud of droplets that spreads in time. Simulation of droplets’ motions showed that inhalation and deposition of droplets inside the receptor airway in the deceleration phase of inhalation were more than in the acceleration phase. In addition, the aspiration of droplets in the first breathing cycle after the cough was more than in the second cycle. Furthermore, results showed that maximum regional deposition occurred in the vestibule, and the penetration of droplets in the left lower lobe and right lower lobe was more than in other lung lobes. Finally, the deposition and penetration of droplets in the right lung were more than in the left lung.

中文翻译：

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静态空气条件下真实循环呼吸下单次咳嗽产生的液滴吸入和气道沉积的数值研究

这项研究分析了感染者单次咳嗽事件产生的飞沫在受体者气道中的吸入和沉积。为此，考虑在静态空调条件下，两个人形人体模型面对面，彼此相距 0.5 m。模拟中包括健康受体人的气道从鼻孔延伸到第4肺代末端。还模拟了受体人体模型的真实循环呼吸。假设感染者的咳嗽事件发生在受体者呼吸的呼气时。所有仿真均采用Ansys-Fluent软件，并采用SST湍流模型来模拟咳嗽、吸气和周围气流场。使用拉格朗日粒子轨迹分析方法模拟咳嗽液滴运动。用于改进 DRW 模型的用户定义函数已开发并实施到 Ansys-Fluent 软件中。气流场模拟结果表明，咳嗽喷射流导致咳嗽人体模型附近形成涡流。在短暂的咳嗽射流过程中，涡流会及时形成和演变。此外，咳嗽事件会产生一团飞沫，并及时扩散。液滴运动模拟表明，吸入减速阶段液滴在受体气道内的吸入和沉积量多于加速阶段。此外，咳嗽后第一个呼吸周期吸入的飞沫量比第二个周期多。此外，结果表明，最大的区域沉积发生在前庭，并且左下叶和右下叶的液滴渗透程度高于其他肺叶。最后，右肺的飞沫沉积和渗透量多于左肺。