Particle deposition in the human tracheobronchial airways due to transient inspiratory flow patterns

Li, Zheng; Kleinstreuer, Clement; Zhang, Zhe

doi:10.1016/j.jaerosci.2007.03.010

Cited by 85 publications

(51 citation statements)

References 44 publications

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“…It seems such a quasi-steady status should be existing when just considering the variation and absolute value of the flow rate or Reynolds number in the alveolar region is much lower than in the proximal airway. However, though the particle transport and deposition is not studied in this work, it is reasonable to say the possibility of the existing of a quasi-steady status is low: the ''scattered streamlines'' pattern, which are not observed as part of the flow patterns in the proximal lung airways [20], is quite different at different wall-expansion rates. This disqualified an important theoretical background for the existing of a quasi-steady status: the main characteristic of the flow pattern in different stages in a transient period should be similar.…”

Section: Discussionmentioning

confidence: 90%

“…It is of interesting to know if a quasi-steady status could be found to match the particle deposition fraction of a transient status, which has been studied in proximal airways [20]. It seems such a quasi-steady status should be existing when just considering the variation and absolute value of the flow rate or Reynolds number in the alveolar region is much lower than in the proximal airway.…”

Section: Discussionmentioning

confidence: 99%

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Airflow analysis in the alveolar region using the lattice-Boltzmann method

Kleinstreuer

2011

Med Biol Eng Comput

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A validated lattice-Boltzmann code has been developed based on the Bhatnagar-Gross-Krook formulation to simulate and analyze transient laminar two-dimensional airflow in alveoli and bifurcating alveolated ducts with moving walls, representative of the human respiratory zone. A physically more realistic pressure boundary condition has been implemented, considering a physiological Reynolds number range, i.e., 0 < Re < 11, which covers the inhalation scenarios from resting mode to moderate exercise. Axial velocity contours, vortex propagation, and streamlines as well as mid-plane pressure variations in different alveolar geometries and shapes are illustrated and discussed. The results show that the influence of the geometric structure on the airflow fields in the human alveolar region is very important. Furthermore, the effect of a moving alveolus wall is significant, i.e., the vortices in the duct or alveolar sacs may change in size. In summary, for a given set of realistic inlet conditions, the airflow velocity and vortical flows are greatly dependent on the different alveolar sac shapes, local geometric structures, and sac expansion rates. The pressure distributions are less influenced by the alveolus shape and wall movement. The present results provide new physical insight and are important for the simulation of particle transport/deposition in the deep lung region.

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Section: Discussionmentioning

confidence: 90%

Section: Discussionmentioning

confidence: 99%

Airflow analysis in the alveolar region using the lattice-Boltzmann method

Kleinstreuer

2011

Med Biol Eng Comput

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“…anatomically realistic geometries [29,46]. These studies found that a realistic geometrical representation is highly important for accurate local deposition information when using Lagrangian particle tracking for the aerosol particle transport.…”

Section: Eulerianlagrangian Methodsmentioning

confidence: 95%

“…[27], the transport of aerosol in the respiratory tract is dependent on the geometric features of the airways, as well as transient effects, which may significantly influence particle deposition. In addition, turbulence in the upper airways also strongly affects particle deposition [28,29]. The mechanisms governing the transport of aerosols in the respiratory system are shown in Fig.…”

Section: Aerosol Transport Evolution and Depositionmentioning

confidence: 99%

Aerosol Dosimetry Modeling Using Computational Fluid Dynamics

Nordlund

Kuczaj

2015

Methods in Pharmacology and Toxicology

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In this chapter, the current state of the art in modeling and prediction of aerosol deposition in respiratory systems using computational fluid dynamics (CFD) is presented and reviewed. First, the physical and chemical processes governing aerosol transport, evolution, and deposition are described followed by their coupling via fundamental conservation laws. The different ways to numerically model aerosol dynamics are then described and a brief overview of the different methods that can be used to obtain a realistic geometry, computational mesh, and simulation conditions of the respiratory system is given. A short review of available numerical algorithms to solve the systems of strongly coupled partial differential equations is also presented followed by a brief discussion of the importance of proper model verification and validation. To complete the path between the inhaled aerosol and the toxicological effects, attempts to couple deterministic CFD-based aerosol deposition modeling with biological effects via physiologically based pharmacokinetic (PBPK) models are described. Finally, conclusions and the current general trends in the application of CFD to toxicological science are given.

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“…It was shown in numerical studies [1,8], however, that the flow field for the non-planar configuration differs significantly from the planar case. Studies considering asymmetric bifurcations [9], non-smooth surfaces [10] and CT-based models [2,5,11] show that the inspiratory flow in the upper human airways is asymmetric and swirling and the results emphasize the importance of realistic airway models. Generally, the aforementioned results show that an accurate lung geometry, i.e., CT data or a real human lung cast, is required to obtain physically relevant results.…”

Section: Introductionmentioning

confidence: 95%

Numerical investigation of the flow field in the upper human airways

Eitel

o}der

Meinke

2009

Modelling in Medicine and Biology VIII

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The flow in a realistic model of the human lung is numerically simulated at steady and unsteady inspiration and expiration. A model of a human lung ranging from the trachea down to the sixth generation of the bronchial tree is used for the simulation. The numerical analysis is based on the Lattice-Boltzmann method, which is particularly suited for flows in extremely intricate geometries such as the upper human airways.The results for steady air flow at inspiration and expiration for a diameter based Reynolds number of Re D = 1250 evidence secondary vortex structures and air exchange mechanisms. It is shown that the asymmetric geometry of the human lung plays a significant role for the development of the flow field in the respiratory system. Secondary vortex structures observed in former studies are reproduced and described in detail.The solutions for unsteady respiration allow a detailed analysis of the temporal formation of secondary flow structures whereas the time dependence is much more pronounced at inspiration than at expiration.

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Particle deposition in the human tracheobronchial airways due to transient inspiratory flow patterns

Cited by 85 publications

References 44 publications

Airflow analysis in the alveolar region using the lattice-Boltzmann method

Airflow analysis in the alveolar region using the lattice-Boltzmann method

Aerosol Dosimetry Modeling Using Computational Fluid Dynamics

Numerical investigation of the flow field in the upper human airways

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