Computational Fluid Dynamics Simulations of Inspiratory Airflow in the Human Nose and Nasopharynx

Subramaniam, Ravi P.; Richardson, Regina B.; Morgan, Kevin T.; Kimbell, Julia S.; Guilmette, Raymond A.

doi:10.1080/089583798197772

Cited by 231 publications

(195 citation statements)

References 13 publications

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“…Depending on the patient-specific anatomy of the nasal cavity, the location and shape of the vortices in the airway may change [21]. In the present study, the complex flow and vortices in the nasal valve region and immediately after the nasal valve are similar to experimental results of Doorly et al [19].…”

Section: Gas Phasesupporting

confidence: 80%

“…The advancement of CFD as well as the digital image processing sciences in the recent decades allows for a precise simulation of the nasal airflow and the particle dispersion and deposition pattern in the patient-specific nasal cavity. 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].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

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

Farnoud

Cui

Baumann

et al. 2017

Proceedings ILASS–Europe 2017. 28th Conference on Liquid Atomization and Spray Systems

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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.

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Section: Gas Phasesupporting

confidence: 80%

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

Farnoud

Cui

Baumann

et al. 2017

Proceedings ILASS–Europe 2017. 28th Conference on Liquid Atomization and Spray Systems

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“…The total volume of the two compartments is adjusted equivalent to average volume of extra-thoracic of Indian women (Varghese et al, 2005). The volume-tosurface-area ratio is used for the calculation of the cross-sectional area based on Subramaniam et al (1998). Due to the complex nature of the NP region, deposition studies typically rely on empirical or logistic models.…”

Section: Growth and Deposition In Nasopharyngeal Regionmentioning

confidence: 99%

Particle Deposition in Human Respiratory Tract: Effect of Water-Soluble Fraction

Varghese

Gangamma

2006

Aerosol Air Qual. Res.

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In the nearly saturated human respiratory tract, the presence of water-soluble substances in inhaled aerosols can cause change in the size distribution of particles. This consequently alters the lung deposition profiles of the inhaled airborne particles. The magnitude of particle deposition in the lung is affected by the soluble component present in the particle. This is estimated by a numerical model. The model solves the condensation growth equation to determine the size evolution of respirable particles within the human respiratory tract. The water uptake by the particles in the respiratory tract results in change of size and density of the particles, and these changes are incorporated for estimating the particle deposition efficiency. The model results are compared with experimental results of sodium chloride particles. The model reproduces the major features of the experimental data. The simulations indicate that the particle can grow up to two times or more of its original size due to water uptake, depending on the quantity of the soluble matter it carries and thus can have significant effect on particle deposition efficiency. The study investigated the effect of soluble compounds in estimating total and regional lung dose of ambient particulate matter measured in Mumbai, India. The particle mass size distribution and composition considered for the ambient particulate matter, the variation in the total mass dose due to the growth was modest. But, the regional lung dose was significantly affected by the hygroscopic growth.

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“…Other studies have highlighted the physical significance of transient breathing (Shi et al, 2006), inlet velocity profiles (Keyhani et al, 1995;Subramaniam et al, 1998), nasal wall motion (Fodil et al, 2005), nasal valve change (Bridger 1970;Bridger and Proctor 1970) and glottal aperture variation (Brancatisano et al, 1983;. Moreover, each nasal model in this study is based on images of one single subject and does not account for the intersubject variability (Hilberg et al, 1993;Pickering and Beardsmore 1999).…”

Section: Discussionmentioning

confidence: 99%

Ultrafine and Fine Aerosol Deposition in the Nasal Airways of a 9-Month-Old Girl, a 5-Year-Old Boy and a 53-Year-Old Male

Xi¹,

Kim²,

Xiuhua³

2012

The Continuum of Health Risk Assessments

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Computational Fluid Dynamics Simulations of Inspiratory Airflow in the Human Nose and Nasopharynx

Cited by 231 publications

References 13 publications

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

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

Particle Deposition in Human Respiratory Tract: Effect of Water-Soluble Fraction

Ultrafine and Fine Aerosol Deposition in the Nasal Airways of a 9-Month-Old Girl, a 5-Year-Old Boy and a 53-Year-Old Male

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