CFD modeling of airborne pathogen transmission of COVID-19 in confined spaces under different ventilation strategies

Abstract

Airborne transmission is an important route of spread of viral diseases (e.g., COVID-19) inside the confined spaces. In this respect, computational fluid dynamics (CFD) emerged as a reliable and fast tool to understand the complex flow patterns in such spaces. Most of the recent studies, nonetheless, focused on the spatial distribution of airborne pathogens to identify the infection probability without considering the exposure time. This research proposes a framework to evaluate the infection probability related to both spatial and temporal parameters. A validated Eulerian-Lagrangian CFD model of exhaled droplets is first developed and then evaluated with an office case study impacted by different ventilation strategies (i.e., cross- (CV), single- (SV), mechanical- (MV) and no-ventilation (NO)). CFD results were analyzed in a bespoke code to calculate the tempo-spatial distribution of accumulated airborne pathogens. Furthermore, two indices of local and general infection risks were used to evaluate the infection probability of the ventilation scenarios. The results suggest that SV has the highest infection probability while SV and NO result in higher dispersions of airborne pathogens inside the room. Eventually, the time history of indices reveals that the efficiency of CV and MV can be poor in certain regions of the room.

Finding the proper position of supply and return registers of air condition system in a conference hall in term of COVID-19 virus spread

“…They found that when the supply register is at the bottom, and the return register is at the top, it is the best form to reduce the concentration of pathogenic particles. Motamedi et al [11] proposed a framework to assess the infection probability under different ventilation strategies. Kotb et al [12] studied how the virus spreads through coughing and sneezing in an airplane cabin and concluded that sneezing is more contagious than coughing, because sneezing droplets travel longer distances.…”

Ventilation Strategies for Mitigation of Infection Disease Transmission in an Indoor Environment: A Case Study in Office

“…Therefore, improving ventilation efficiency is critical in the face of large ventilation demand [21]. From the perspective of airflow pattern, the development of efficient ventilation systems and ventilation modes can contribute to mitigating the transmission of infectious disease and improving the energy saving efficiency [22].…”

Analysis of occupants’ exposure risk of cough-expelled droplets in the workspace with various mixing ventilation layouts

“…Among these, risk assessment in relation to human exposure to infectious droplets play a vital role in the early stage of the disease transmission investigation (Nicas et al, 2005). Due to the human exposure risk is closely linked to the occupants exposed to pathogen-bearing droplets for a given time period that is influenced by various affecting factors (e.g., ventilation), it could be a good reference to reflect the effectiveness of the implemented measures (Motamedi et al, 2022). Recently, with the increasing demand for conducting a robust and fast evaluation of human indoor exposure risks, the use of CFD-based simulation is becoming more popular as it can cost-effectively assess the exposure risk by visualising detailed droplet trajectories (Peng et al, 2020).…”