AAAR 31st Annual Conference
October 8-12, 2012
Hyatt Regency Minneapolis
Minneapolis, Minnesota, USA
Abstract View
Particle Detachment, Resuspension and Dispersion Due to Human Induced Flow Field in Gate Cycle
IMAN GOLDASTEH, Yilin Tian, Kyung Sul, Goodarz Ahmadi, Andrea R. Ferro, Clarkson University
Abstract Number: 261 Working Group: Indoor Aerosols
Abstract Particulate matter (PM) is an important component of air pollution in the indoor environment. Among the sources of PM, particle resuspension from flooring during human walking contributes substantially to the concentration of particles larger than 1 micrometer. Earlier studies showed that high speed airflows generated at the floor level between the shoe and flooring during the gate cycle is the main reason of for particle resuspension. The details of the resuspension mechanism and the subsequent particle dispersion, however, are not well understood.
In this study a combined experimental and computational studies were performed to shed light on the mechanisms of particle detachment from flooring during the gait cycle and the corresponding resuspesnion and dispersion in indoor environment. A mechanical foot experimental set up was developed and used to measure the rate of resuspension for a range of conditions. The mechanical foot device mimics human walking and may be used to generate reproducible data for particle resuspension. In addition, a three dimensional numerical model of a shoe during the walking cycle was developed using the FLUENT$^(TM) software. The Reynolds Averaged Navier-Stokes (RANS) approach in conjunction with the k-ε turbulence model was used for simulating the unsteady airflow field around the shoe during the gait cycle. To account for the real motion of the shoe, a user defined function (UDF) was developed and the dynamic mesh method was used. Particulate phase resuspension and dispersion was modeled using the Lagrangian particle tracking approach. Particle detachment was analyzed using the recently developed Monte Carlo resuspension model that was incorporated in the FLUENT code with the use of the UDF. Physical characteristics of particle/flooring morphology and material properties were taken into account in the model simulation. The resuspension of particles due to human walking was estimated and the results were compared with the experimentally measured particle concentrations. It was shown that the computational model predictions are in good agreement with the experimental data.