Dynamics of airflow in a short inhalation

During a rapid inhalation, such as a sniff, the flow in the airways accelerates and decays quickly. The consequences for flow development and convective transport of an inhaled gas were investigated in a subject geometry extending from the nose to the bronchi. The progress of flow transition and the...

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Bibliographic Details
Published in:Journal of the Royal Society interface 2015-01, Vol.12 (102), p.20140880-20140880
Main Authors: Bates, A. J., Doorly, D. J., Cetto, R., Calmet, H., Gambaruto, A. M., Tolley, N. S., Houzeaux, G., Schroter, R. C.
Format: Article
Language:English
Subjects:
Airways
Biomechanics
Bronchi - physiology
CFD
Computer Simulation
Enginyeria biomèdica
Flux
Gases
Gasos
Humans
Inhalation - physiology
Inspiratory Flow
Internal Flow
Male
Middle Aged
Models, Anatomic
Models, Theoretical
Neck - diagnostic imaging
Pulmonary Ventilation
Radiography, Thoracic
Respiration
Respiratory Tract
Stress, Mechanical
Time Factors
Tomography, X-Ray Computed
Transitional Flow
Àrees temàtiques de la UPC
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Summary:During a rapid inhalation, such as a sniff, the flow in the airways accelerates and decays quickly. The consequences for flow development and convective transport of an inhaled gas were investigated in a subject geometry extending from the nose to the bronchi. The progress of flow transition and the advance of an inhaled non-absorbed gas were determined using highly resolved simulations of a sniff 0.5 s long, 1 l s−1 peak flow, 364 ml inhaled volume. In the nose, the distribution of airflow evolved through three phases: (i) an initial transient of about 50 ms, roughly the filling time for a nasal volume, (ii) quasi-equilibrium over the majority of the inhalation, and (iii) a terminating phase. Flow transition commenced in the supraglottic region within 20 ms, resulting in large-amplitude fluctuations persisting throughout the inhalation; in the nose, fluctuations that arose nearer peak flow were of much reduced intensity and diminished in the flow decay phase. Measures of gas concentration showed non-uniform build-up and wash-out of the inhaled gas in the nose. At the carina, the form of the temporal concentration profile reflected both shear dispersion and airway filling defects owing to recirculation regions.
ISSN:1742-5689
1742-5662
1742-5662
DOI:10.1098/rsif.2014.0880