Study of indoor ventilation to mitigate COVID transmission using chemical reactor model and computational fluid dynamic simulation

Indoor ventilation plays a key role in controlling air-borne infection spread of the COVID-19 virus. The transmission rate in a given scenario can be calculated using a fully-mixed reactor model, which assumes that the pathogen is uniformly distributed in the entire volume of air in the room and that all parts of the room are equally ventilated. This is not the case in many real scenario, where regions of trapped or dead air may be present at corners and around obstacles in a room. It is found that the rate of evacuation of infectious particle floating in the air can be up to ten times slower from dead air zones.

Computational fluid dynamic simulations of the air flow in a given room can be used to ascertain the location and extent of the recirculating regions. CFD simulation solves the conservation equations of fluid motion to obtain the air flow velocity field. Discrete particle method is used to get the concentration of infectious particles in different parts of the room. This can be combined with pathogen production/deactivation and air purification rates to get the pathogen concentration. The concentration is then used to study the probability of infection from an infected person to other susceptible people in the room.

This project is in collaboration with Prof. Krishnendu Sinha (Aerospace engineering) and Prof. Janani Murallidharan (Mechanical engineering).