Applications of a coupled Multizone-CFD model to calculate airflow and contaminant dispersion in built environments for emergency management

Current simulation tools for airflow and contaminant dispersion in built environments cannot provide detailed information with little computing effort, which is critical for emergency management. Multizone airflow network models are fast but cannot provide detailed flow and contaminant transport information in an indoor space. Computational fluid dynamics (CFD), on the other hand, gives very detailed information but requires hours or days of computing time on a PC. A coupled multizone-CFD model can offer detailed information on contaminant dispersion while reducing computing time. The study presented in this paper applied the coupled model to calculate airflow and contaminant dispersion in a three-story, naturally ventilated building with a large atrium, assuming that a contaminant was released in the atrium. This investigation studied the effectiveness using emergency ventilation to protect the building occupants. It was demonstrated that the coupled model can provide important information of contaminant distributions with a reasonable computing time. The information is useful for evaluating placement of contaminant sensors and determining evacuation strategies for emergency management.