CFD analysis of the flow structure in a monkey upper airway validated by PIV experiments

Phuong, Nguyen Lu; Quang, Tran; Khoa, Nguyễn Đăng; Kim, Ji Woong; Ito, Kazuhide

doi:10.1016/j.resp.2019.103304

Cited by 16 publications

(6 citation statements)

References 40 publications

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“…All flow fields in the respiratory tracts were analyzed using a low‐Reynolds number‐type, k–ε turbulence model (Abe–Kondoh–Nagano model), which was designed to account for damping and echo effects in near‐wall regions. The Abe–Kondoh–Nagano turbulence model has been adopted for various flow‐field analysis types, from laminar to turbulent, and has exhibited good prediction accuracy in enclosed space flow‐field analyses 45‐51 . The conservation of mass and momentum was solved by applying the finite volume method (FVM), which allowed the use of an unstructured mesh for complicated models such as that of an upper airway.…”

Section: Methodsmentioning

confidence: 99%

“…The Abe-Kondoh-Nagano turbulence model has been adopted for various flow-field analysis types, from laminar to turbulent, and has exhibited good prediction accuracy in enclosed space flowfield analyses. [45][46][47][48][49][50][51] The conservation of mass and momentum was solved by applying the finite volume method (FVM), which allowed the use of an unstructured mesh for complicated models such as that of an upper airway. Continuity and Reynolds-averaged Navier-Stokes (RANS) equations were numerically calculated for steady, incompressible, and isothermal flows, as shown in Equations ( 1) and (2):…”

Section: Airflow Analysis In the Human Respiratory Systemmentioning

confidence: 99%

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Transport and deposition of inhaled man‐made vitreous and asbestos fibers in realistic human respiratory tract models: An in silico study

Khoa

Phuong

Takahashi

et al. 2022

Japan Architectural Review

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Particles longer than 5 μm and with a length/diameter ratio >3 are defined as fibers. Asbestos or other fibers are still identified in residential environments due to the emission from asbestos-used building materials. The respiratory system is the primary route of asbestos exposure; under a longer residence time, asbestosrelated adverse health effects are inevitable. Currently, asbestos fibers have been replaced with man-made vitreous fibers (MMVFs); however, studies have revealed some similar biological effects of MMVFs with asbestos. Therefore, MMVFs-induced diseases need to be determined by analyzing their deposition characteristics and foci in human respiratory tracts. In this study, we used computational fluid dynamics method to investigate fibers' airflow and deposition patterns in two realistic human respiratory models. Two drag models were used to predict the deposition of uniform 1 μm (asbestos) and 3.66 μm (carbon fiber-CF) diameter, 15-300 μm long fibers. Two drag models provided comparable results with the experimental data. Comparatively, asbestos deposition was independent of fiber length, while CF deposition increased proportionally to fiber length. The highest level of local deposition was detected in the anterior nasal cavity. The results obtained from this study can extend current knowledge of human vitreous fiber exposure-related lung diseases. Keywords asbestos, computational fluid dynamics, drag force, human respiratory system, man-made vitreous fiber (MMVF)-like carbon fiberThis is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.

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Section: Methodsmentioning

confidence: 99%

Section: Airflow Analysis In the Human Respiratory Systemmentioning

confidence: 99%

Transport and deposition of inhaled man‐made vitreous and asbestos fibers in realistic human respiratory tract models: An in silico study

Khoa

Phuong

Takahashi

et al. 2022

Japan Architectural Review

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“…The term Reynolds stresses ij= 𝑢 𝑖 ′ 𝑢 𝑗 ′ states the closure problem to the RANS equation; therefore, the turbulent model was selected to account for the closure problem. This study applied the low-Reynolds-type k- (Abe Kondoh Nagano) turbulent model, which has been shown to provide a reliable prediction of airflow in the respiratory model [11,12]. Different breathing flow rates of 7.5 and 30 L/min were selected to cover the resting and intensive human activities.…”

Section: Airflow Simulationmentioning

confidence: 99%

“…Currently, computer resources facilitate sophisticated studies relating to fluid dynamics in a complex structure such as the human lower airway, and the costly and ethical barriers of experiments on living entities, for example, in vivo or in vitro, further emphasize the need for numerical simulation utilizing growing computer power [10]. Presently, the computational fluid dynamics (CFD) method has been adopted as a promising alternative that can provide an accurate simulation of airflow in the complex structure of the respiratory tract [11,12], as well as the deposition of virus-laden droplets and viral load [13]. Several simulation efforts have been performed to characterize inhaled particle behavior in the lower airway using a perfect tube-like geometry [14,15], or a realistic model [16,17].…”

Section: Introductionmentioning

confidence: 99%

Numerical Investigation of Fine particle Transportation and Deposition in the Human Lower Airway: Impact of airflow and particle size on deposition efficiency

Khoa¹,

Phuong²,

Ito³

2022

Proceedings of International Exchange and Innovation Conference on Engineering &Amp; Sciences (IEICES)

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Understanding the deposition of inhaled toxic particles is critical in evaluating numerous health risks, especially in the lower airway. Recently, the computational fluid dynamics (CFD) method has been introduced as a promising method to facilitate the accurate prediction of airflow and particle behavior in complex geometry. Therefore, this study applied the CFD method to investigate the deposition characteristic of fine particles in the human respiratory tract from the nostrils to the 7 th generation. The airflow pattern was simulated using the Eulerian method at breathing flow rates of 7.5 and 30 L/min, and was followed by particle (aerodynamic diameter 1 to 10 m) deposition simulation using the Lagrangian method. In general, the results were comparable with experimental data. The high deposited concentration of particles was found at the 5-7 th generation, and a specific deposition hot-spot was observed at the carina ridge.

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“…As the respiratory tracts of rodents and humans are anatomically very different, drastic interspecies differences are expected for predicted particle deposition results, especially the regional deposition 22 . Because non‐human primates (such as monkey) share higher level of structural and functional similarity with humans, monkeys are thus better human surrogate for inhalation toxicity tests 23‐26 …”

Section: Introductionmentioning

confidence: 99%

Numerical analysis of nanoparticle transport and deposition in a cynomolgus monkey nasal passage

Dong

Tian

et al. 2021

Numer Methods Biomed Eng

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Environmental exposure to toxic agents is commonly encountered by occupational and residential populations. However, in vivo exposure data in human subjects is limited by measurement and ethical restrictions. Monkey represents a suitable surrogate for human exposure studies, but the particle transport and deposition features in monkey airways are still not well understood. As a response to this research challenge, this paper presents a virtual exposure study that numerically investigated the nanoparticle transport process through a realistic cynomolgus monkey nasal airway. Particles with size of 1 nm to 1 μm were considered and the transport process was modelled by the Lagrangian discrete phase model. Overall and local deposition as well as particle dispersion along the airway were examined by using a variety of non‐dimensional parameters including combined diffusion parameter, deposition enhancement factor and particle flux enhancement factor. Consistent deposition patterns were observed in present and literature nasal models. Most particles tended to pass the nasal airway through certain spatial regions, including the middle section of the nasal valve, the lower half of the middle coronal plane, and the central regions of the choana. While naturally inhaled nanoparticles can hardly be delivered to the olfactory region as it is located apart from the mainstream with high particle flux. Research findings provide insight into nanoparticle inhalation exposure characteristics in the monkey airway and can contribute in formulating data extrapolation schemes between monkey and human airways.

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CFD analysis of the flow structure in a monkey upper airway validated by PIV experiments

Cited by 16 publications

References 40 publications

Transport and deposition of inhaled man‐made vitreous and asbestos fibers in realistic human respiratory tract models: An in silico study

Transport and deposition of inhaled man‐made vitreous and asbestos fibers in realistic human respiratory tract models: An in silico study

Numerical Investigation of Fine particle Transportation and Deposition in the Human Lower Airway: Impact of airflow and particle size on deposition efficiency

Numerical analysis of nanoparticle transport and deposition in a cynomolgus monkey nasal passage

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