Numerical simulation of particle deposition in the human nasal cavity

Based on the CT scanned images, a realistic geometric model from nasal cavity to upper six-generation bronchia is rebuilt. In order to effectively simulate the particle movement and deposition, LES model is used and the particles are tracked in the frame of Lagrange. Seven kinds of typical particles, including micron particles (1, 5, and 10 μm) and nanoparticles (1, 5, 20, and 100 nm), and three representative respiratory intensities are adopted as computational case, respectively. Deposition efficiency ( D E), deposition concentration ( D C), and capture efficiency ( C E) are introduced. Furthermore, the locations of particle deposition are visualized. The results indicate that the injecting particles from different nasal inlet present “transposition effect.”The D E values of micron particles are much higher than nanoparticles. The particle diameter plays a weaker role in nanoparticle depositions than micron particles. The highest values of D E and D C both occur in nasal cavity, while the highest C E up to 99.5% occurs in bronchus region.

Download Full-text

Numerical Simulation of the Aerosol Particle Motion in Granular Filters with Solid and Porous Granules

Processes ◽

10.3390/pr9020268 ◽

2021 ◽

Vol 9 (2) ◽

pp. 268

Author(s):

Olga V. Soloveva ◽

Sergei A. Solovev ◽

Ruzil R. Yafizov

Keyword(s):

Numerical Simulation ◽

Aerosol Particle ◽

Particle Deposition ◽

Particle Diameter ◽

Deposition Efficiency ◽

Hydrodynamic Resistance ◽

Hydrodynamic Properties ◽

Granular Filters ◽

Limiting Value ◽

Good Agreement

In this work, a study was carried out to compare the filtering and hydrodynamic properties of granular filters with solid spherical granules and spherical granules with modifications in the form of micropores. We used the discrete element method (DEM) to construct the geometry of the filters. Models of granular filters with spherical granules with diameters of 3, 4, and 5 mm, and with porosity values of 0.439, 0.466, and 0.477, respectively, were created. The results of the numerical simulation are in good agreement with the experimental data of other authors. We created models of granular filters containing micropores with different porosity values (0.158–0.366) in order to study the micropores’ effect on the aerosol motion. The study showed that micropores contribute to a decrease in hydrodynamic resistance and an increase in particle deposition efficiency. There is also a maximum limiting value of the granule microporosity for a given aerosol particle diameter when a further increase in microporosity leads to a decrease in the deposition efficiency.

Download Full-text

Numerical Simulation of Powder Dispersion Performance by Different Mesh Types

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.680.82 ◽

2016 ◽

Vol 680 ◽

pp. 82-85

Author(s):

Jian Cai ◽

Lan Chen ◽

Umezuruike Linus Opara

Keyword(s):

Numerical Simulation ◽

Flow Field ◽

Fine Particle ◽

Particle Deposition ◽

Tetrahedral Mesh ◽

Computational Time ◽

Kinetic Characteristics ◽

Powder Dispersion ◽

Simulation Results ◽

Time Accuracy

OBJECTIVE To investigate the influence of mesh type on numerical simulating the dispersion performance of micro-powders through a home-made tube. METHODS With the computational fluid dynamics (CFD) method, a powder dispersion tube was meshed in three different types, namely, tetrahedral, unstructured hexahedral and prismatic-tetrahedral hybrid meshes. The inner flow field and the kinetic characteristics of the particles were investigated. Results of the numerical simulation were compared with literature evidences. RESULTS The results showed that using tetrahedral mesh had the highest computational efficiency, while employing the unstructured hexahedral mesh obtained more accurate outlet velocity. The simulation results of the inner flow field and the kinetic characteristics of the particles were slightly different among the three mesh types. The calculated particle velocity using the tetrahedral mesh had the best correlation with the changing trend of the fine particle mass in the first 4 stages of the new generation impactor (NGI) (R2 = 0.91 and 0.89 for powder A and B, respectively). Conclusions Mesh type affected computational time, accuracy of simulation results and the prediction abilities of fine particle deposition.

Download Full-text