AAAR 31st Annual Conference
October 8-12, 2012
Hyatt Regency Minneapolis
Minneapolis, Minnesota, USA
Abstract View
Quantification of Leakages in Respirators using Computational Fluid Dynamics
SUVAJYOTI GUHA, Matthew Myers, Prasanna Hariharan, Food and Drug Administration
Abstract Number: 732 Working Group: Health Related Aerosols
Abstract Masks and respirators constitute an important component of strategies for protection against hazardous bioaerosols. In order to optimally prepare for any event involving release of bioaerosols, it is advantageous to have techniques available that can quantify the reduction in risk associated with the use of a new barrier design, or with an existing barrier in the presence of a new hazard. We have begun development of a technique that utilizes computed tomography (CT) scans to identify gaps between masks and facial profiles, and computational fluid dynamics (CFD) to characterize the particle transmission through the gaps. Multiple facial profiles will be obtained for different ethnicities, for both adults and children. This poster focuses on the validation stages of the technique, where respirators were attached to flat plates with known gap profiles. CT images of the gap profiles were obtained, and a segmentation program was employed to create finite-volume meshes from the imaged gap volumes. Finite-volume CFD computations of particle transport in and around the gaps are being performed, using a “coefficient of restitution model” to treat interaction of the aerosol with the plate and respirator. The CFD code will be validated experimentally for the flat plate model using a collision type aerosol generator for producing polydispersed NaCl aerosols and a laser aerosol spectrometer for characterizing these leakages in the 100 – 1000 nm size range. In the future, both the CFD and experimental techniques will be extended to human manikins.