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Pantelis G. Koullapis
Computational Sciences Laboratory (UCY-CompSci) Department of Mechanical and Manufacturing Engineering University of Cyprus, University Avenue 1, 2109 Nicosia, Cyprus

Stavros C. Kassinos
Department of Mechanical Engineering Stanford University Stanford, California 94305 USA; Department of Mechanical and Manufacturing Engineering, Computational Sciences Laboratory, UCY-COMPSCI University of Cyprus, Nicosia, Cyprus

Ching-Long Lin
Department of Mechanical and Industrial Engineering, and IIHR-Hydroscience and Engineering, The University of Iowa, Iowa City, Iowa 52242


In the current study, Large Eddy Simulations (LES) are used to investigate the transport and deposition of inhaled aerosol particles (dp = 0.1, 0.5, 1, 2.5, 5, 10µm) in a realistic geometry of the human airways under steady inhalation. The effects of electrostatic charge and lower generation airway narrowing caused by Chronic Obstructive Pulmonary Disease (COPD) on particle transport and deposition are examined for various flowrates (sedentary - 15.2 lt/min, light - 30 lt/min and heavy activity - 60 lt/min). Results show that the mean flow structures at the three flowrates are qualitatively similar regardless of Reynolds number. Similar swirling motions are generated from the impingement of the laryngeal jet on the tracheal front wall. However, higher turbulent intensities that persist further downstream in the trachea and the main bronchi are observed as the flowrate is increased. The Deposition Efficiency (DE) of particles is increased with the flowrate due to greater inertial impaction. The majority of the larger particles are filtered in the mouththroat region, while 0.1, 0.5 and 1µm diameter particles have similar DE at a given flowrate. The effect of charge on DE of particles is more pronounced for smaller particles; 1000 elementary charge units on 0.1, 0.5, 1 and 2.5 µm diameter particles results in approximately 7, 3, 2.5 and 1.5 times greater overall DE than that with no charge, respectively. Obstructed lower generation airways result in enhanced deposition due to impaction caused by higher velocities in these airways.