Simulated Mucus Clearance in Horizontal vs. Vertically Inclined Rigid Tracheal Model

Abstract Epithelia of conducting airways is lined with a layer of mucus above a layer of serous fluid. Mucus is a viscoelastic gel, while the serous layer is identified as “watery”. In normal airways, the mucociliary transport system forms the primary basis for clearance of mucus. Dehydration results in the disappearance of serous layer and impairs the mucociliary clearance. For these persons two-phase gas-liquid flow and cough become the dominant mechanisms.

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Mucus clearance by two-phase gas-liquid flow mechanism: asymmetric periodic flow model

Journal of Applied Physiology ◽

10.1152/jappl.1987.62.3.959 ◽

1987 ◽

Vol 62 (3) ◽

pp. 959-971 ◽

Cited By ~ 75

Author(s):

C. S. Kim ◽

A. J. Iglesias ◽

M. A. Sackner

Keyword(s):

Flow Rate ◽

Liquid Flow ◽

Flow Model ◽

Horizontal Tube ◽

Tube Model ◽

Flow Mechanism ◽

Inspiratory Flow Rate ◽

Two Phase ◽

Mucus Clearance ◽

Gas Liquid Flow

Mucus transport by two-phase gas-liquid flow mechanism was investigated with in vitro flow models under asymmetric periodic airflow conditions with nine different liquid solutions with rheological properties similar to human sputum. The flow model was made with 1.0-cm-ID glass tube and positioned either vertically or horizontally. With a constant supply of the test liquids into the model tube (0.5 ml/min), the liquid layer transport speed (LLTS) as well as the mean liquid layer thickness at steady-state condition (hs) was measured in conjunction with various airflow patterns of different expiratory and inspiratory flow rate, breathing frequency (f), and tidal volume (VT). The flow patterns were maintained within the range of normal breathing. In the horizontal tube model, LLTS ranged from 1.14 +/- 0.02 to 3.39 +/- 0.04 cm/min at the peak expiratory flow rate (VEp) of 30–60 l/min. The inspiratory flow rate, as well as f and VT did not affect LLTS. However, LLTS increased with increasing VEp, and at the same VEp LLTS was higher with viscoelastic than with viscous liquid. In the vertical tube model, the upward transport of mucus could not be achieved at VEp lower than 30 l/min particularly with low viscosity and low elasticity fluid. However, at high values of VEp, LLTS was comparable to that in the horizontal tube model with viscoelastic fluid, whereas LLTS of viscous liquid showed 26–40% lower than that in the horizontal tube model. The value of hs was 5–20% of the tube diameter at VEp of 30–60 l/min in both models. These results indicate that effective mucus clearance can be achieved by two-phase gas-liquid flow mechanism in patients with excessive bronchial secretions with biased tidal breathing favoring the expiratory flow and that the clearance can be further promoted by changing rheological properties of mucus.

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Gas-liquid flow density meter in the composition of a two-phase flowmeter for gas-condensate and oil-gas-condensate wells

Automation Telemechanization and Communication in Oil Industry ◽

10.33285/0132-2222-2019-2(547)-16-22 ◽

2019 ◽

pp. 16-22

Author(s):

I.N. Moskalev ◽

◽

A.O. Chistyakov ◽

A.V. Semenov ◽

◽

...

Keyword(s):

Liquid Flow ◽

Gas Condensate ◽

Flow Density ◽

Two Phase ◽

Gas Liquid Flow ◽

Oil Gas

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VOID FRACTION DISTRIBUTION IN TWO-PHASE GAS-LIQUID FLOW IN INCLINED PIPES

Proceeding of International Heat Transfer Conference 10 ◽

10.1615/ihtc10.5620 ◽

1994 ◽

Author(s):

Klaus Spindler

Keyword(s):

Void Fraction ◽

Liquid Flow ◽

Two Phase ◽

Void Fraction Distribution ◽

Fraction Distribution ◽

Gas Liquid Flow ◽

Inclined Pipes

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Numerical modeling of the influence of bubbles on flow and heat transfer in the descending gas-liquid flow in a pipe

Proceedings of the Mavlyutov Institute of Mechanics ◽

10.21662/uim2012.1.025 ◽

2012 ◽

Vol 9 (1) ◽

pp. 131-135

Author(s):

M.A. Pakhomov

Keyword(s):

Heat Transfer ◽

Gas Phase ◽

Liquid Flow ◽

Bubble Diameter ◽

Gas Content ◽

Two Phase ◽

Eulerian Description ◽

Flow And Heat Transfer ◽

Gas Liquid Flow ◽

The Mathematical Model

The paper presents the results of modeling the dynamics of flow, friction and heat transfer in a descending gas-liquid flow in the pipe. The mathematical model is based on the use of the Eulerian description for both phases. The effect of a change in the degree of dispersion of the gas phase at the input, flow rate, initial liquid temperature and its friction and heat transfer rate in a two-phase flow. Addition of the gas phase causes an increase in heat transfer and friction on the wall, and these effects become more noticeable with increasing gas content and bubble diameter.

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