AAAR 36th Annual Conference October 16 - October 20, 2017 Raleigh Convention Center Raleigh, North Carolina, USA
Abstract View
Aerosol Deposition Efficiency Model for Exposure Systems with Diffusion-Sedimentation Driven Aerosol Transport
FRANCESCO LUCCI, Arkadiusz Kuczaj, Philip Morris International R&D
Abstract Number: 296 Working Group: Aerosol Exposure
Abstract The modern multi-well aerosol exposure systems deliver sampled aerosol to a large number of biological samples (tissue cultures) at the air-liquid interface (e.g. Vitrocell, Cultex). Typical flow in an in-vitro exposure chamber geometry is laminar and at low-velocity at the aerosol exposure conditions. The aerosol mixture is brought to the tissue surface and turns along to leave the dilution/distribution system in the so-called trumpet-like shaped geometry. The operating sampling flowrate conditions to the exposure chamber dictate the aerosol dynamics in the system, its residence time and also deposition mechanisms. This flowrate is also constrained from the biological perspective in order to avoid large shear forces and evaporation acting in the system that could dry-out and potentially damage the tissue culture.
By applying our recently developed Eulerian modeling framework for simulations of the polydisperse multi-species aerosol transport and deposition, we have investigated aerosol deposition efficiency at varying geometry of exposure chambers, aerosol properties, and operating conditions. We have found that for the recommended operating conditions the aerosol deposition is mainly driven by the size-dependent sedimentation velocity and diffusion mechanisms. In the confirmed absence of inertial impaction, we have proposed a simple and very robust size-dependent model of aerosol deposition, which is generally applicable to different exposure systems and operative conditions by taking into account flow and geometry parameters. The proposed model was validated on the basis of experimental results finding good agreement with the available literature data.