Expiratory Virus Dispersion Throughout a Working Environment

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Commercial Heating, Ventilation and Air Conditioning (HVAC) systems aim at creating ideal working environments for employees. While accommodating higher or lower room temperature desires, work area concentrations often suffer from insufficient ventilation and mixing to prevent or minimize exposure to the expiratory viruses released from sneezing and coughing. Computational Fluid Dynamics (CFD) simulations, analyzing air flow diffusion within an office environment along with a single cough were performed. The domain for this investigation includes a current engineering office setting and a cough dispersing cold virus particles. Simulations were performed using commercial CFD code STAR-CCM+® from CD-adapco as an implicit unsteady K-ω (Menter) SST turbulence model with segregated flow and segregated temperature to solve the unsteady Reynolds-Averaged Navier-Stokes equations. Results pertaining to a Lagrangian flow field specification include particle distribution throughout the room, particle velocity, residence time, and particle count with an emphasis on breathing zones. Simulations were performed for air flow with zero, 30% and 60% relative humidity. Results indicate that greater humidity, compared to lower or no levels of humidity at all, clearly has an effect on the dispersion of particles and the distance they travel within a room. Over identical periods of time, particle dispersion was greater with zero humidity and demonstrated a decrease in dispersion with 30% and even less dispersion over 60%  humidity.

Author Company: 
California State University, Long Beach
Author Name: 
Berton Vite