Air Quality Management in Railway Coaches

With the outbreak of COVID-19 all over the world, it has become increasingly important to understand and effectively manage air quality in enclosed environments. The effect of HVAC (Heating, Ventilation, and Air Conditioning) systems in airborne disease transmission is crucial especially in confined public places such as hospitals, buses, and railway coaches. Computational Fluid Dynamics has become an important tool for studying and understanding the behaviors of fluid flow especially aerosol transport in such enclosed spaces. The current paper focuses on simulating the behavior of air in the indoor environment of a railway coach under four different conditions. These are where the rail coach has no occupants and with three occupants with the effect of three and six different HVAC supply air inlet conditions explored. The results show that without occupants, the air from the inlet spreads into the coach with relatively low velocity and maintains its speed throughout the coach until at the outlet where it speeds up. With occupants in the coach, the incoming air was observed to spread wide and exits the coach with much higher velocity. This is due to the reduced available flow area occasioned by the occupants, and this information will be useful in further studies with aerosol transport within the coach.