Abstract
To respond to the ongoing pandemic of SARS-CoV-2, this contribution deals with recently highlighted COVID-19 transmission through respiratory droplets in form of aerosols. Unlike other recent studies that focused on airborne transmission routes, this work addresses aerosol transport and deposition in a human respiratory tract. The contribution therefore conducts a computational study of aerosol deposition in digital replicas of human airways, which include the oral cavity, larynx and tracheobronchial airways down to the 12th generation of branching. Breathing through the oral cavity allows the air with aerosols to directly impact the larynx and tracheobronchial airways and can be viewed as one of the worst cases in terms of inhalation rate and aerosol load. The implemented computational model is based on Lagrangian particle tracking in Reynolds-Averaged Navier–Stokes resolved turbulent flow. Within this framework, the effects of different flow rates, particle diameters and lung sizes are investigated to enable new insights into local particle deposition behavior and therefore virus loads among selected age groups. We identify a signicant increase of aerosol deposition in the upper airways and thus a strong reduction of virus load in the lower airways for younger individuals. Based on our findings, we propose a possible relation between the younger age related fluid mechanical protection of the lower lung regions due to the airway size and a reduced risk of developing a severe respiratory illness originating from COVID-19 airborne transmission.
Highlights
Flows with dispersed particles are of great interest, since they can be found in numerous fields of engineering and medical science
To solve the problem the considered lung geometries were generated by a dedicated scaling of the adult lung of Koullapsis et al [18], and used in computational models to study general trends in deposition of aerosols
The computational model is based on Reynolds Averaged Navier Stokes (RANS) equations with k-ω-SST model employed to account for the turbulent flow in the airways
Summary
Flows with dispersed particles are of great interest, since they can be found in numerous fields of engineering and medical science. In this context, the ongoing COVID-19 pandemic can be considered as a recent topic. The virus is known to be transmissible via contacts and droplets as well as aerosols [32,38]. In many studies aerosols are defined as particles with a diameter dp ≤ 5 μ m and larger particles as droplets [11,36]. Thomas et al [33] stated that larger particles
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
