Computational Modeling and Validation of Aerosol Deposition in Ventilation Ducts

In fire models, the accurate prediction of aerosol and soot concentrations in the gas phase and their deposition thicknesses in the condensed phase is important for a wide range of applications, including human egress calculations, heat transfer in compartment fires, and forensic reconstructions. During a fire, in addition to soot transport by advection and diffusion, a significant amount of soot can be deposited on surfaces due to various mechanisms. As a first approach of quantifying aerosol deposition predictions under non-reacting flow conditions, this study identifies important parameters under various flow conditions and compares predicted aerosol deposition quantities to experimentally measured data. The computational tool used in this study was the computational fluid dynamics code, Fire Dynamics Simulator (FDS). Model predictions are compared to measured deposition velocities for various sizes of monodisperse fluorescent particles and various air velocities at the ceiling, wall, and floor of a ventilation duct.