Evaluation of local gas transport rate in oscillatory flow in a model of human central airways

Gaku Tanaka, Jin Ito, Kotaro Oka, Kazuo Tanishita

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

The rate of local axial gas transport in oscillatory flow through a model of human central airways was measured to evaluate gas exchange during high-frequency oscillation. A rigid model of human central airways consists of asymmetrical bifurcations up to 3-5 generation, of which geometries were determined by the study of Horsfield et al. A bolus of CO2 tracer was injected into the trachea, and effective diffusivities as a function of location in the airways were obtained from CO2 washout profiles. The rate of increase of effective diffusivity depends on the local flow conditions and differs with branches. The effective diffusivity in the left main bronchus is 3.2 times greater than that in the straight tube, whereas no significant difference is observed in the right main bronchus. In addition, the presence of a stationary period augments axial gas transport in intermittent oscillatory flow because it provides time for the occurrence of lateral mixing in the radial direction, i. e., axial diffusivity is 1.6 times greater on the average than that in sinusoidally oscillatory flow.

Original languageEnglish
Pages (from-to)1946-1954
Number of pages9
JournalNippon Kikai Gakkai Ronbunshu, B Hen/Transactions of the Japan Society of Mechanical Engineers, Part B
Volume63
Issue number610
DOIs
Publication statusPublished - 1997 Jan 1
Externally publishedYes

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Mechanical Engineering

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