Influence of internal heating and natural convection on airborne transmission of viral diseases

We conduct large eddy simulations in a canonical room of size 10x10x3.2m3 subject to mechanical ventilation to assess the impact of internal heating on droplet nuclei dispersal in indoor spaces. We conduct two simulations with a solitary heat source placed at the center of the room in the first, and 16 heat sources arranged in an equidistant non-staggered formation in the second. The heat sources mimic heat generation from an adult person. The simulations employ a statistical overloading approach where 10 million droplet nuclei are individually monitored for approximately one hour in real-time. These results are then compared to previous simulations that share identical setup and procedures but do not account for any thermal load. We assess the effect of internal heat sources on multiple levels by averaging over all possible positions of the infected (source) and the susceptible (sink) occupants within the room. We find that, at the room-average level, the room concentration, which results from a balance of droplet nuclei production through expiratory events and removal through various mechanisms is unaffected by the presence of heat sources. On the other hand, the spatial and temporal dispersion of droplet nuclei, as observed from the standpoint of a known source or sink location, or when a combination of sources and sinks at fixed separation distances is considered, is significantly influenced by the presence of heat sources.