10th International Aerosol Conference September 2 - September 7, 2018 America's Center Convention Complex St. Louis, Missouri, USA
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Deposition of Length-classified Glass Fibers in a Replica of Human Airways
FRANTISEK LIZAL, Miloslav Belka, Jakub Elcner, Jan Jedelsky, Ondrej Misik, Jan Tuhovcak, Miroslav Jicha, Brno University of Technology
Abstract Number: 94 Working Group: Health Related Aerosols
Abstract Inhalable fibers form a specific group of particles, which are provably, or potentially toxic for humans [1]. A few studies applied computational fluid and particle dynamics (CFPD) calculations for prediction of localised deposition of fibers [2]. However, obtaining reliable experimental data for validation represents significant problem for all teams performing numerical simulations.
A realistic replica of human airways has been developed at Brno University of Technology. The identical geometry exists as a physical replica for experimental work and as a digital geometry for numerical simulations [3].
The results on flow and deposition of spherical particles were published in [4]. In this contribution we introduce measurement of deposition of length-classified fibers.
Experimental setup The measurements setup was described in detail in [5]. Glass wool (Johns Manville JM 100/475) was crushed and sieved to produce fibers with a density of 2.56 g/cm3 and diameter of 1.03 ± 0.45 µm. The fibers were classified using a dielectrophoretic classifier, mixed with clean air, and sucked into the replica. Three steady inhalation flowrates (15, 30 and 50 L/min) were measured. Counting of fibers was performed by a combination of manual and automated counting [5].
Results and discussion The deposition fraction increased with an increasing flow rate, and the total deposition fractions in the replica were 0.7%, 1.9% and 4.6% for the inspiratory flow rates of 15, 30, and 50 LPM, respectively. A slightly higher deposition fraction was detected in the oral cavity and in the complex segments. Moreover, segments in the right lung that encompassed a bifurcation in the fourth generation had a noticeably higher deposition fraction for higher inspiratory flow rates.
A comparison of deposition fractions for fibers and spherical particles confirmed that fibers deposit less effectively than spherical particles of the same Stokes number. The results of local deposition fraction, efficiency and density are available for validation of numerical simulations performed on the identical airway geometry.
Acknowledgement The authors would like to acknowledge the financial support provided by the Czech Science Foundation under the grant GA 18-25618S, and the COST-European Cooperation in Science and Technology, Action MP1404: Simulation and pharmaceutical technologies for advanced patient-tailored inhaled medicines (SimInhale).
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