A numerical framework for the analysis of indoor air quality in a classroom
Mohamed Mahmoud Abdelkareem Mahmoud, Prateek Bahl, A. F. V. de A. Aquino, C Raina Maclntyre, Subhadeep Bhattacharjee, Donna Green, Nathan Cooper, Con J. Doolan, Charitha de Silva
Abstract
This paper presents a framework for applying Computational Fluid Dynamics (CFD) to study indoor air quality in a classroom environment by analysing the transport and extent of human-generated aerosol and carbon dioxide (CO2) accumulation. A methodology is outlined for identifying the appropriate amounts of exhaled aerosol and CO2 needed as boundary conditions for human breathing in CFD simulations, which is validated with in situ measurements obtained within a stale air classroom environment at matched conditions. This is crucial for quantifying the exhaled CO2 and aerosols from occupants, which is essential for designing ventilation settings that promote a healthy indoor environment. Good agreement is observed between the CFD and experiments for CO2 and aerosol concentration within the size range of 0.7-1 μm. Further, we explore the impact of individual heat sources and breathing momentum flux on air stratification and aerosol dispersion. The analysis reveals that the thermal plume generated by each occupant and the momentum created from breathing are the characteristics of airflow in a stale air environment. This paper demonstrates the ability of the developed numerical model to reproduce realistic exhaled aerosol and CO2 in indoor ventilation settings, serving as a benchmark for investigating indoor air quality in the built environment.