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Investigation of the Air Flow in a generic Model of the Lung: Analysis of the Governing Transport Mechanisms

Lars Krenkel
Institute of Aerodynamics and Flow Technology, Dept. Fluid Systems German Aerospace Center (DLR) Bunsenstr.10, 37073 Gottingen, Germany

Claus Wagner
German Aerospace Center (DLR), Institute for Aerodynamics and Flow Technology, Bunsenstrasse 10, 37073 Göttingen, Germany; Ilmenau University of Technology, Institute of Thermodynamics and Fluid Mechanics, Germany

Аннотация

The central airways of the lung are a complex system of bifurcations and pipes. In the case of artificial ventilation support with the necessity of using airway management devices (i.e. endotracheal tubes) the complexity of the system even increases and a complete understanding of the ventilation and oxygenation mechanisms is of major interest in order to ensure protective oxygenation and ventilation of the patient.
Numerical investigations on the influence of endotracheal tubes on the flow revealed that thesel tubes have an important impact within the trachea and accordingly in the central airways of the lung. A parametric study on the effect of the tube's level of detail on the resulting flow regime showed that it is necessary to model not only the tube's ending but also the bending which is essential for the development of secondary flows.
A comparison of numerical data generated with a turbulent and a laminar Navier-Stokes solver revealed that for the indistinct, potentially transitional flow in the airways with endotracheal tube the simulations with turbulence model are more promising but in terms of computational costs more expensive.