Numerical Simulation of Dusty Air Flow and Particle Deposition Inside Permeable Alveolar Duct

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.

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Numerical Simulation of Droplets Moving on Surface of Three-Dimensional Trapezoidal Object in Air Flow(Fluids Engineering)

TRANSACTIONS OF THE JAPAN SOCIETY OF MECHANICAL ENGINEERS Series B ◽

10.1299/kikaib.76.768_1134 ◽

2010 ◽

Vol 76 (768) ◽

pp. 1134-1143 ◽

Cited By ~ 1

Author(s):

Katsunori DOI ◽

Takeshi KAWANABE ◽

Naoki HAMAMOTO ◽

Yoshiaki NAKAMURA

Keyword(s):

Numerical Simulation ◽

Air Flow ◽

Three Dimensional

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Numerical Modelling Of Humid Air Flow Around A Porous Body

Acta Mechanica et Automatica ◽

10.1515/ama-2015-0027 ◽

2015 ◽

Vol 9 (3) ◽

pp. 161-166

Author(s):

Aneta Bohojło-Wiśniewska

Keyword(s):

Heat Transfer ◽

Numerical Simulation ◽

Porous Medium ◽

Numerical Modelling ◽

Chinese Cabbage ◽

Air Flow ◽

Transfer Model ◽

Humid Air ◽

Ansys Fluent ◽

Complex Heat Transfer

Summary This paper presents an example of humid air flow around a single head of Chinese cabbage under conditions of complex heat transfer. This kind of numerical simulation allows us to create a heat and humidity transfer model between the Chinese cabbage and the flowing humid air. The calculations utilize the heat transfer model in porous medium, which includes the temperature difference between the solid (vegetable tissue) and fluid (air) phases of the porous medium. Modelling and calculations were performed in ANSYS Fluent 14.5 software.

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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.

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Numerical simulation of high inertial liquid-in-gas droplet in a T-junction microchannel

RSC Advances ◽

10.1039/c7ra09710g ◽

2017 ◽

Vol 7 (77) ◽

pp. 48512-48525 ◽

Cited By ~ 14

Author(s):

Mohammad Mastiani ◽

Babak Mosavati ◽

Myeongsub (Mike) Kim

Keyword(s):

Numerical Simulation ◽

Air Flow ◽

Flow Regimes ◽

Droplet Generation ◽

Aqueous Droplet

Two new flow regimes named unstable dripping and unstable jetting are identified in aqueous droplet generation within high inertial air flow inside a T-Junction microchannel.

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Flow structures and particle deposition patterns in double-bifurcation airway models. Part 2. Aerosol transport and deposition

Journal of Fluid Mechanics ◽

10.1017/s0022112001003810 ◽

2001 ◽

Vol 435 ◽

pp. 55-80 ◽

Cited By ~ 79

Author(s):

J. K. COMER ◽

C. KLEINSTREUER ◽

C. S. KIM

Keyword(s):

Particle Deposition ◽

Air Flow ◽

Reynolds Numbers ◽

Companion Paper ◽

Stokes Number ◽

Vortical Flow ◽

Flow Structures ◽

Particle Distributions ◽

Deposition Patterns ◽

Inlet Conditions

The flow theory and air flow structures in symmetric double-bifurcation airway models assuming steady laminar, incompressible flow, unaffected by the presence of aerosols, has been described in a companion paper (Part 1). The validated computer simulation results showed highly vortical flow fields, especially around the second bifurcations, indicating potentially complex particle distributions and deposition patterns. In this paper (Part 2), assuming spherical non-interacting aerosols that stick to the wall when touching the surface, the history of depositing particles is described. Specifically, the finite-volume code CFX (AEA Technology) with user-enhanced FORTRAN programs were validated with experimental data of particle deposition efficiencies as a function of the Stokes number for planar single and double bifurcations. The resulting deposition patterns, particle distributions, trajectories and time evolution were analysed in the light of the air flow structures for relatively low (ReD1 = 500) and high (ReD1 = 2000) Reynolds numbers and representative Stokes numbers, i.e. StD1 = 0.04 and StD1 = 0.12. Particle deposition patterns and surface concentrations are largely a function of the local Stokes number, but they also depend on the fluid–particle inlet conditions as well as airway geometry factors. While particles introduced at low inlet Reynolds numbers (e.g. ReD1 = 500) follow the axial air flow, secondary and vortical flows become important at higher Reynolds numbers, causing the formation of particle-free zones near the tube centres and subsequently elevated particle concentrations near the walls. Sharp or mildly rounded carinal ridges have little effect on the deposition efficiencies but may influence local deposition patterns. In contrast, more drastic geometric changes to the basic double-bifurcation model, e.g. the 90°-non-planar configuration, alter both the aerosol wall distributions and surface concentrations considerably.

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