Simulation of airflow fields and microparticle deposition in realistic human lung airway models. Part I: Airflow patterns

Li, Zheng; Kleinstreuer, Clement; Zhang, Zhe

doi:10.1016/j.euromechflu.2007.02.003

Cited by 60 publications

(26 citation statements)

References 23 publications

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“…As the Womersley numbers are 2.3 and 3.1 for resting and moderate exercise situations, it is of interest to investigate the transient effects in the complex airway geometry (Pedley, 1977). While the transient effects on the flow fields have been studied by Li et al (2007aLi et al ( , 2007b, this paper focuses on the particle deposition dynamics for transient inhalation.…”

Section: Airflow Equationsmentioning

confidence: 99%

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

Kleinstreuer

Zhang

2007

Journal of Aerosol Science

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Section: Airflow Equationsmentioning

confidence: 99%

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

Kleinstreuer

Zhang

2007

Journal of Aerosol Science

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“…Several papers deal with laminar flow, such as Piglione et al (2012), who solved the flow field in the central airways where a laminar flow is expected. Li et al (2007) solved the upper tracheobronchial tree with realistic transient waveform inspiration and proved that secondary flow occurs during flow deceleration. Ghalati et al (2012), meanwhile, analyzed the flow field in the upper airways and mouth/throat cavity with micro-and nano-particle deposition.…”

Section: Introductionmentioning

confidence: 99%

Numerical investigation of inspiratory airflow in a realistic model of the human tracheobronchial airways and a comparison with experimental results

Elcner

Lízal

Jedelský

et al. 2015

Biomech Model Mechanobiol

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In this article, the results of numerical simulations using computational fluid dynamics (CFD) and a comparison with experiments performed with phase Doppler anemometry are presented. The simulations and experiments were conducted in a realistic model of the human airways, which comprised the throat, trachea and tracheobronchial tree up to the fourth generation. A full inspiration/expiration breathing cycle was used with tidal volumes 0.5 and 1 L, which correspond to a sedentary regime and deep breath, respectively. The length of the entire breathing cycle was 4 s, with inspiration and expiration each lasting 2 s. As a boundary condition for the CFD simulations, experimentally obtained flow rate distribution in 10 terminal airways was used with zero pressure resistance at the throat inlet. CCM+ CFD code (Adapco) was used with an SST k-ω low-Reynolds Number RANS model. The total number of polyhedral control volumes was 2.6 million with a time step of 0.001 s. Comparisons were made at several points in eight cross sections selected according to experiments in the trachea and the left and right bronchi. The results agree well with experiments involving the oscillation (temporal relocation) of flow structures in the majority of the cross sections and individual local positions. Velocity field simulation in several cross sections shows a very unstable flow field, which originates in the tracheal laryngeal jet and propagates far downstream with the formation of separation zones in both left and right airways. The RANS simulation agrees with the experiments in almost all the cross sections and shows unstable local flow structures and a quantitatively acceptable solution for the time-averaged flow field.

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“…However, this previous study made a number of simplifying assumptions, such as a symmetric double bifurcation geometry, steady laminar flow conditions, and relatively large submicrometer particles. Recent studies by Nowak et al, 66 van Ertbruggen et al, 84 and Li et al 43 all suggest that idealized symmetrical bifurcations are not sufficient to simulate deposition in human lungs and that more anatomically accurate models may be required. In addition, Lin et al 45 implemented a CT-based intrathoracic airway model and highlighted enhanced local turbulence entering the tracheobronchial region as a result of the laryngeal jet.…”

Section: Introductionmentioning

confidence: 96%

Evaluation of a Drift Flux Model for Simulating Submicrometer Aerosol Dynamics in Human Upper Tracheobronchial Airways

Longest

2008

Ann Biomed Eng

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In this study, a hybrid drift flux velocity correction (DF-VC) model that accounts for both submicrometer particle diffusion and inertia was extended to transient conditions and was tested against existing experimental deposition data measured in a replica cast of the human tracheobronchial (TB) region for laminar and turbulent flow. To evaluate the effectiveness of the DF-VC model, deposition results were compared with a standard chemical species (CS) approach that neglects particle inertia. A numerical model of the TB cast was constructed from CT images and extended from the larynx to approximately the sixth respiratory generation. Experimentally determined inlet and outlet flow conditions were implemented in the computational model to ensure direct comparisons between simulations and measurements for the deposition of 40 and 200 nm particles. A low Reynolds number k-omega turbulence model was employed to resolve the laminar and turbulent flow regimes that coexist in the TB geometry. Interesting flow characteristics were observed due to the presence of the larynx, asymmetrical ventilation, and left-right asymmetry, which created a right-skewed laryngeal jet and flow reversal in the trachea that persist over a majority of the transient flow cycle. In comparison with the CS model, deposition results of the DF-VC approach persistently agreed better with experimental findings on a total and sub-branch basis, which indicated that the DF-VC model effectively captured the influence of finite particle inertia. For the submicrometer aerosols considered, transient flows were observed to increase deposition arising from impaction and decrease deposition arising from diffusion on a total and segmental basis compared with steady state conditions. However, the maximum deposition enhancement factor was significantly increased under transient conditions for both 40 nm (factor of 2) and 200 nm (factor of 7) aerosols. Results of this study indicate that a drift flux particle transport model with near-wall velocity corrections can provide an effective continuous-field approach for simulating the transport and deposition of submicrometer respiratory aerosols in human upper TB airways.

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Simulation of airflow fields and microparticle deposition in realistic human lung airway models. Part I: Airflow patterns

Cited by 60 publications

References 23 publications

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

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

Numerical investigation of inspiratory airflow in a realistic model of the human tracheobronchial airways and a comparison with experimental results

Evaluation of a Drift Flux Model for Simulating Submicrometer Aerosol Dynamics in Human Upper Tracheobronchial Airways

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