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Particle Transport and Deposition under High-Frequency Oscillatory Ventilation and Normal Breathing

The fluid mechanics of high-frequency oscillatory ventilation (HFOV) for gas transport in the pulmonary region of the human lungs have been thoroughly studied by different methods. The major concept of HFOV adaptation is to push gas into further generation of the bronchial tree, with adequate gas mixing and small tidal volume. However, particle transport and deposition under HFOV is a rarely studied case where different mechanisms, compared to the mechanisms of gas transport, may associate. The target of this study is to numerically compare the efficiency of particle drug deposition under HFOV to normal breathing (NB) and to further clarify the mechanisms of particle transport and deposition under oscillating flows. A fully Eulerian computational fluid particles dynamic (CFPD) model is used for studying the transport and deposition of several sizes of inertia particles, under different transient flow conditions, inside a single physiologically realistic bifurcation created by generations G3–G4 of the human lung. An insight into the particle dynamics under high-frequency oscillating flow fields is given and the results showed that the highly oscillating field (HFOV) displayed stronger secondary flows, thinner boundary layers, and strong counter flow that accumulate and deposit particles further than a lower frequency oscillatory field (NB). Copyright 2014 American Association for Aerosol Research