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 language | English |
|---|---|
| Pages (from-to) | 686-692 |
| Number of pages | 7 |
| Journal | Nippon Kikai Gakkai Ronbunshu, C Hen/Transactions of the Japan Society of Mechanical Engineers, Part C |
| Volume | 63 |
| Issue number | 607 |
| Publication status | Published - 1997 Mar |
| Externally published | Yes |
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ASJC Scopus subject areas
- Mechanical Engineering
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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 journal › Article
}
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
AN - SCOPUS:0031099348
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 -