Effect of wall conductivity on axial gas dispersion in oscillatory flow

Hideki Fujioka, Kotaro Oka, Kazuo Tanishita

Research output: Contribution to journalArticle

Abstract

High-frequency oscillation (HFO) is an artificial respiratory system based on small tidal volume and high frequency. Axial gas dispersion in an oscillatory flow occurs due to the interaction between radial mixing and radially nonuniform axial velocity profile. Furthermore, the dispersion can be improved by intermittent oscillatory flow. Most previous studies employ the insulating trachea wall model. However, an actual airway wall has conductivity and absorptivity of flowing gas. In the present study, numerical simulation of CO2 gas transport in an oscillatory flow through an infinitely long straight airway was carried out to reveal the effect of wall conductivity on axial CO2 gas transport in oscillatory flow. The ratio of resultant effective diffusivity to the effective diffusivity of the insulating wall was markedly enhanced if β<1, due to the gas exchange on the wall. The maximum ratio was more than 200 in this computation. Furthermore, by employing intermittent oscillatory flow, CO2 gas transport resistance was improved in all airway regions, because of radial diffusion during stationary period in thick airways and wall gas exchange in thin airways.

Original languageEnglish
Pages (from-to)686-692
Number of pages7
JournalNippon Kikai Gakkai Ronbunshu, C Hen/Transactions of the Japan Society of Mechanical Engineers, Part C
Volume63
Issue number607
Publication statusPublished - 1997 Mar

Fingerprint

Gases
Respiratory system
Computer simulation

ASJC Scopus subject areas

  • Mechanical Engineering

Cite this

Effect of wall conductivity on axial gas dispersion in oscillatory flow. / Fujioka, Hideki; Oka, Kotaro; Tanishita, Kazuo.

In: Nippon Kikai Gakkai Ronbunshu, C Hen/Transactions of the Japan Society of Mechanical Engineers, Part C, Vol. 63, No. 607, 03.1997, p. 686-692.

Research output: Contribution to journalArticle

@article{076aace864e7447f9c18d68361d52be0,
title = "Effect of wall conductivity on axial gas dispersion in oscillatory flow",
abstract = "High-frequency oscillation (HFO) is an artificial respiratory system based on small tidal volume and high frequency. Axial gas dispersion in an oscillatory flow occurs due to the interaction between radial mixing and radially nonuniform axial velocity profile. Furthermore, the dispersion can be improved by intermittent oscillatory flow. Most previous studies employ the insulating trachea wall model. However, an actual airway wall has conductivity and absorptivity of flowing gas. In the present study, numerical simulation of CO2 gas transport in an oscillatory flow through an infinitely long straight airway was carried out to reveal the effect of wall conductivity on axial CO2 gas transport in oscillatory flow. The ratio of resultant effective diffusivity to the effective diffusivity of the insulating wall was markedly enhanced if β<1, due to the gas exchange on the wall. The maximum ratio was more than 200 in this computation. Furthermore, by employing intermittent oscillatory flow, CO2 gas transport resistance was improved in all airway regions, because of radial diffusion during stationary period in thick airways and wall gas exchange in thin airways.",
author = "Hideki Fujioka and Kotaro Oka and Kazuo Tanishita",
year = "1997",
month = "3",
language = "English",
volume = "63",
pages = "686--692",
journal = "Nihon Kikai Gakkai Ronbunshu, C Hen/Transactions of the Japan Society of Mechanical Engineers, Part C",
issn = "0387-5024",
publisher = "Japan Society of Mechanical Engineers",
number = "607",

}

TY - JOUR

T1 - Effect of wall conductivity on axial gas dispersion in oscillatory flow

AU - Fujioka, Hideki

AU - Oka, Kotaro

AU - Tanishita, Kazuo

PY - 1997/3

Y1 - 1997/3

N2 - High-frequency oscillation (HFO) is an artificial respiratory system based on small tidal volume and high frequency. Axial gas dispersion in an oscillatory flow occurs due to the interaction between radial mixing and radially nonuniform axial velocity profile. Furthermore, the dispersion can be improved by intermittent oscillatory flow. Most previous studies employ the insulating trachea wall model. However, an actual airway wall has conductivity and absorptivity of flowing gas. In the present study, numerical simulation of CO2 gas transport in an oscillatory flow through an infinitely long straight airway was carried out to reveal the effect of wall conductivity on axial CO2 gas transport in oscillatory flow. The ratio of resultant effective diffusivity to the effective diffusivity of the insulating wall was markedly enhanced if β<1, due to the gas exchange on the wall. The maximum ratio was more than 200 in this computation. Furthermore, by employing intermittent oscillatory flow, CO2 gas transport resistance was improved in all airway regions, because of radial diffusion during stationary period in thick airways and wall gas exchange in thin airways.

AB - High-frequency oscillation (HFO) is an artificial respiratory system based on small tidal volume and high frequency. Axial gas dispersion in an oscillatory flow occurs due to the interaction between radial mixing and radially nonuniform axial velocity profile. Furthermore, the dispersion can be improved by intermittent oscillatory flow. Most previous studies employ the insulating trachea wall model. However, an actual airway wall has conductivity and absorptivity of flowing gas. In the present study, numerical simulation of CO2 gas transport in an oscillatory flow through an infinitely long straight airway was carried out to reveal the effect of wall conductivity on axial CO2 gas transport in oscillatory flow. The ratio of resultant effective diffusivity to the effective diffusivity of the insulating wall was markedly enhanced if β<1, due to the gas exchange on the wall. The maximum ratio was more than 200 in this computation. Furthermore, by employing intermittent oscillatory flow, CO2 gas transport resistance was improved in all airway regions, because of radial diffusion during stationary period in thick airways and wall gas exchange in thin airways.

UR - http://www.scopus.com/inward/record.url?scp=0031099348&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0031099348&partnerID=8YFLogxK

M3 - Article

VL - 63

SP - 686

EP - 692

JO - Nihon Kikai Gakkai Ronbunshu, C Hen/Transactions of the Japan Society of Mechanical Engineers, Part C

JF - Nihon Kikai Gakkai Ronbunshu, C Hen/Transactions of the Japan Society of Mechanical Engineers, Part C

SN - 0387-5024

IS - 607

ER -