3D printed respiratory tract enables studies of airborne disease dispersal

When you sneeze, how far do the droplets — and any pathogens they carry — travel? This question became a matter of public safety during the COVID-19 pandemic. Many research projects attempted to study how aerosols spread using volunteers coughing and sneezing. This method, however, led to large inconsistencies due to individual respiratory differences.

To overcome this issue, Catalán et al. developed an experimental setup for consistent coughing.

“The main idea was to replicate coughing and sneezing in a reproducible way,” said author Salvatore Cito. “Being in the mechanical department, we thought we could create an experimental model that wouldn’t be expensive.”

The authors 3D printed an anatomically accurate upper respiratory system with a nose, throat, and mouth. Connecting it to a pump and tank that acted as the system’s lungs, they were able to create consistent sneezes and coughs. A high speed camera captured the projection of droplets, which were illuminated by a laser light. The resulting data was used to create a model for how a sneeze cloud disperses.

The findings will help other researchers in the field benchmark their own numerical simulations.

“To keep simulations reasonable and computationally affordable, you have to make some simplifications, and most of these simplifications are focused on the geometry of these airways,” said author Alexandre Fabregat. “We found that these airway geometries are actually really important.”

In addition to improving simulations, the findings and setup can help create guidelines for social distancing and enable better mask design. The researchers are continuing the work with a study on the effects of ambient air temperature on droplet dispersion.

Source: “Effects of Nasal Cavity and Exhalation Dynamics on Aerosol Spread in Simulated Respiratory Events,” by Nicolás Catalán, Salvatore Cito, Sylvana Varela, Alexandre Fabregat, Anton Vernet, and Jordi Pallarès, Physics of Fluids (2024). The article can be accessed at https://doi.org/10.1063/5.0241346 .

This paper is part of the Flow and the Virus Collection, learn more here .