Numerical simulation of aerosol deposition in a 3-D human nasal cavity using RANS, RANS/EIM, and LES

Liu, Yuan; Matida, Edgar; Gu, Junjie; Johnson, Matthew R.

doi:10.1016/j.jaerosci.2007.05.003

Cited by 112 publications

(100 citation statements)

References 32 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This was due to the relatively high inertia of the 50-μm particle size, which is not influenced by local turbulent fluctuations. Since the solution was not sensitive to turbulence-particle interactions, no near-wall turbulence corrections were used in the simulations (25,26). A further study was conducted to investigate the influence of the coefficient of restitution.…”

Section: Computational Fluid Dynamicsmentioning

confidence: 99%

Effect of Device Design on the In Vitro Performance and Comparability for Capsule-Based Dry Powder Inhalers

Shur

Lee

Adams

et al. 2012

AAPS J

View full text Add to dashboard Cite

Abstract. This study investigated the effect of modifying the design of the Cyclohaler on its aerosolization performance and comparability to the HandiHaler at multiple flow rates. The Cyclohaler and HandiHaler were designated as model test and reference unit-dose, capsule-based dry powder inhalers (DPIs), respectively. The flow field, pressure drop, and carrier particle trajectories within the Cyclohaler and HandiHaler were modeled via computational fluid dynamics (CFD). With the goal of achieving in vitro comparability to the HandiHaler, the CFD results were used to identify key device attributes and to design two modifications of the Cyclohaler (Mod 1 and Mod 2), which matched the specific resistance of the HandiHaler but exhibited different cyclonic flow conditions in the device. Aerosolization performance of the four DPI devices was evaluated by using the reference product's capsule and formulation (Spiriva capsule) and a multistage cascade impactor. The in vitro data showed that Mod 2 provided a closer match to the HandiHaler than the Cyclohaler and Mod 1 at 20, 39, and 55 l/min. The in vitro and CFD results together suggest that matching the resistance of test and reference DPI devices is not sufficient to attain comparable aerosolization performance, and the improved in vitro comparability of Mod 2 to the HandiHaler may be related to the greater degree of similarities of the flow rate of air through the pierced capsule (Q c ) and the maximum impact velocity of representative carrier particles (V n ) in the Cyclohaler-based device. This investigation illustrates the importance of enhanced product understanding, in this case through the CFD modeling and in vitro characterization of aerosolization performance, to enable identification and modification of key design features of a test DPI device for achieving comparable aerosolization performance to the reference DPI device.KEY WORDS: computational fluid dynamics; device design; dry powder inhaler; in vitro comparability; in vitro performance.

show abstract

Section: Computational Fluid Dynamicsmentioning

confidence: 99%

Effect of Device Design on the In Vitro Performance and Comparability for Capsule-Based Dry Powder Inhalers

Shur

Lee

Adams

et al. 2012

AAPS J

View full text Add to dashboard Cite

show abstract

“…The first numerical studies of the airflow pattern in the nasal airway were accomplished by Keyhani et al [20] and Subramaniam et al [21]. Recently, particle dispersion and deposition have been studied in realistic nasal airways [22,23,24]. These simulations were performed with the commercial software packages CFX [22] and Fluent [23,24].…”

Section: Introductionmentioning

confidence: 99%

“…Recently, particle dispersion and deposition have been studied in realistic nasal airways [22,23,24]. These simulations were performed with the commercial software packages CFX [22] and Fluent [23,24]. Most of the research in this area considers a steady inlet airflow [25] or an unsteady flow representing inhalation-exhalation cycles [26].…”

Section: Introductionmentioning

confidence: 99%

Numerical Simulation of the Dispersion and Deposition of a Spray Carried by a Pulsating Airflow in a Patient-Specific Human Nasal Cavity

et al. 2017

View full text Add to dashboard Cite

The present numerical study concerns the dispersion and deposition of a nasal spray in a patient-specific human nose. The realistic three-dimensional geometry of the nasal cavity is reconstructed from computer tomography (CT) scans. Identification of the region of interest, removal of artifacts, segmentation, generation of the .STL file and the triangulated surface grid are performed using the software packages ImageJ, meshLab, and NeuRA2. An unstructured computational volume grid with approximately 15 million tetrahedral grid cells is generated using the software Ansys ICEM-CFD 11.0. An unsteady Eulerian-Lagrangian formulation is used to describe the airflow and the spray dispersion and deposition in the realistic human nasal airway using two-way coupling. A new solver called pimpleParcelFoam is developed, which combines the lagrangianParcel libraries with the pimpleFoam solver within the software package OpenFOAM 3.0.0. A large eddy simulation (LES) with the dynamic sub-grid scale (SGS) model is performed to study the spray in both a steady and a pulsating airflow with an inflow rate of 7.5 L/min (or maximum value in case of the pulsating spray) and a frequency of 45 Hz for pulsation as used in commercial inhalation devices. 10,000 mono-disperse particles with the diameters of 2.4 µm and 10 µm are uniformly injected at the nostrils. In order to fulfil the stability conditions for the numerical solution, a constant time-step of 10 −5 s is implemented. The simulations are performed for a real process time of 1 s, since after the first second of the process, all particles have escaped through the pharynx or they are deposited at the surface of the nasal cavity. The numerical computations are performed on the high-performance computer bwForCluster MLS&WISO Production using 256 processors, which take around 32 and 75 hours for steady and pulsating flow simulation, respectively. The study shows that the airflow velocity reaches its maximum values in the nasal valve, in parts of the septum and in the nasopharynx. A complex airflow is observed in the vestibule and in the nasopharynx region, which may directly affect the dispersion and deposition pattern of the spray. The results reveal that the spray tends to deposit in the nasal valve, the septum and in the nasopharynx due to the change in the direction of the airflow in these regions. Moreover, it is found that due to the pulsating airflow, the aerosols are more dispersed and penetrate deeper into the posterior regions and the meatuses where the connections to the sinuses reside.

show abstract

“…However, particles greater than 20 nm did not match the experimental data to a high degree. Liu et al (2007) simulated particles ranging from 0.354-16 µm using three Lagrangian particle tracking models. Results of this study showed that the standard eddy interaction model used for Lagrangian particle tracking in turbulent flows significantly over predicted the deposition of the smaller particles considered.…”

Section: Introductionmentioning

confidence: 99%

Characterization of Submicrometer Aerosol Deposition in Extrathoracic Airways during Nasal Exhalation

Longest

2009

Aerosol Science and Technology

View full text Add to dashboard Cite

Submicrometer and especially fine aerosols that enter the respiratory tract are largely exhaled. However, the deposition of these aerosols under expiratory conditions is not well characterized. In this study, expiratory deposition patterns of both ultrafine (<100 nm) and fine (100-1000 nm) respiratory aerosols were numerically modeled in a realistic nasal-laryngeal airway geometry. Particle sizes ranging from 1 through 1000 nm and exhalation flow rates from 4 through 45 L/min were considered. Under these conditions, turbulence only appeared significant in the laryngeal and pharyngeal regions, whereas the nasal passages were primarily in the laminar regime. Exhaled particles were simulated with both a continuous-phase drift flux velocity correction (DF-VC) model and a discrete Lagrangian tracking approach. For the deposition of ultrafine particles, both models provided a good match to existing experimental values, and simulation results corroborated an existing in vivo-based diffusion parameter (i.e., D 0.5 Q −0.28 ). For fine particles, inertia-based deposition was found to have a greater dependence on the Reynolds number than on the Stokes number (i.e., St 0.1 k Re 0.9 ), indicating that secondary flows may significantly influence aerosol deposition in the nasal-laryngeal geometry. A new correlation was proposed for deposition in the extrathoracic airways that is applicable for both ultrafine and fine aerosols over a broad range of nasal exhalation conditions. Results of this study indicate that physical realism of the airway model is crucial in determining particle behavior and fate and that the laryngeal and pharyngeal regions should be retained in future studies of expiratory deposition in the nasal region.

show abstract

Numerical simulation of aerosol deposition in a 3-D human nasal cavity using RANS, RANS/EIM, and LES

Cited by 112 publications

References 32 publications

Effect of Device Design on the In Vitro Performance and Comparability for Capsule-Based Dry Powder Inhalers

Effect of Device Design on the In Vitro Performance and Comparability for Capsule-Based Dry Powder Inhalers

Numerical Simulation of the Dispersion and Deposition of a Spray Carried by a Pulsating Airflow in a Patient-Specific Human Nasal Cavity

Characterization of Submicrometer Aerosol Deposition in Extrathoracic Airways during Nasal Exhalation

Contact Info

Product

Resources

About