Correlations between flow resistance and geometry in a model of the human nose.
The relationship between the pressure losses within the nasal airways and nasal geometry were studied in a 3:1 scale model. The geometry of the model was based on magnetic resonance images of the skull of a healthy male subject. Pressure measurements, flow visualization, and hot-wire anemometry studies were performed at flow rates that, in vivo, corresponded to flows of between 0.05 and 1.50 l/s. The influence of nasal congestion and the collapse of the external nares were examined by using modeling clay to simulate local constrictions in the cross section. A dimensionless analysis of the pressure losses within three sections of the airway revealed the influence of various anatomic dimensions on nasal resistance. The region of the exterior nose behaves as a contraction-expansion nozzle in which the pressure losses are a function of the smallest cross-sectional area. Losses in the interior nose resemble those associated with channel flow. The nasopharynx is modeled as a sharp bend in a circular duct. Good correspondence was found between the predicted and actual pressure losses in the model under conditions that stimulated local obstructions and congestion.
Schreck
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Department of Biomedical Engineering, University of Southern California, Los Angeles 90089-1451.
Sullivan
K J
KJ
Ho
C M
CM
Chang
H K
HK
D000328:Adult; D000399:Air Pressure; D000403:Airway Resistance / Q000502:physiology*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008953:Models, Anatomic; D009296:Nasal Cavity / Q000033:anatomy & histology / Q000502:physiology; D015508:Nasal Obstruction / Q000503:physiopathology; D009305:Nasopharynx / Q000033:anatomy & histology / Q000502:physiology; D009666:Nose / Q000033:anatomy & histology* / Q000502:physiology*; D014132:Trachea / Q000033:anatomy & histology / Q000502:physiology