Numerical Simulation of Virus-Laden Droplets Transport from Lung to Lung by Using Eighth-Generation Airway Model.

In this study, we simulated the trajectory of virus-laden droplets from the lung of an infected person to that of the exposed person using computational fluid dynamics. As numerical models, the model of the infected person who had a bifurcated airway and that of the exposed person who had an eighth-generation airway were prepared. The volume and number of virus-laden droplets adhered to the inlet patches of the exposed person’s lung were calculated to evaluate the risk of infection when the infected person was talking for 40 s. To identify the lung to which droplets adhered, we labeled the inlet patches of the exposed person’s lung with 53 numbers, and then measured the volume and number of droplets on the inlet patches of lung. We also categorized the lung’s 53 intake patches into five groups and calculated the overall volume and number of attached droplets for each. In addition, we parameterized the angle of the exposed person’s neck to evaluate the effect of the tilting neck on the volume and number of droplets reaching the lungs. We found that the volume and number of droplets adhered to the right middle group of bronchi were remarkably smaller than the other four groups, and weakly depended on the neck angle. The volume and number of droplets adhered to the inlet patches of the lung reached the maximum values when the neck angle was 20° upward.