Detailed Analysis of Fiber Motion in Human Nasal Airways

Abstract Information on the fiber particle transport and deposition in human nasal airways is of great importance in inhalation toxicology study. Due to the complex interactions between the inhaled aerosol particles and human respiratory airways, the particles’ toxicity varies with their chemical composition, size, and shape. In the earlier computational study of fiber particle motion in human nasal cavities, overall deposition efficiency curves were evaluated and compared with the available experimental data. The majority of investigations were on micron-scale fiber particles, and the observed deposition fraction is strongly affected by fiber inertial impaction and the geometry of the cavity. The fiber characterization by its equivalent spheres is still not entirely fully understood. Limited existing evidence indicated that, when benchmarked by the impaction parameter, spherical particles tend to have a higher deposition fraction than that of the elongated fiber particles in the nasal cavity. More data is needed to elaborate on these observations and reveal the underlying physics. A more profound understanding of fiber transport in human airways may be obtained by comparing the fibrous particle deposition to that of the spherical particles. In this study, simulations of transport and deposition of elongated particles in a realistic human nasal cavity model for a steady laminar airflow rate were performed. FLUENT 19.2 was used to solve the airflow conditions. The elongated ellipsoidal particle transport and deposition were simulated using the coupled translational and rotational equations of motion. The hydrodynamic drag and torque, shear-induced lift, and gravitational force were included in the analysis. One-way coupling was assumed, and an in-house User Defined Function (UDF) was developed and was implemented into the ANSYS-FLUENT code for analyzing the fiber transport and deposition. The airflow field, the particle deposition efficiency, particle deposition pattern, and single-particle trajectories of fiber and sphere were analyzed and presented. The simulation results were compared with available experimental data and simulation results in the literature.

Download Full-text

Deposition Fraction of Ellipsoidal Particles in a Fully Developed Laminar Pipe Flow: Application of New Correlations for Hydrodynamic Forces and Torques

Volume 1D, Symposia: Transport Phenomena in Mixing; Turbulent Flows; Urban Fluid Mechanics; Fluid Dynamic Behavior of Complex Particles; Analysis of Elementary Processes in Dispersed Multiphase Flows; Multiphase Flow With Heat/Mass Transfer in Process Technology; Fluid Mechanics of Aircraft and Rocket Emissions and Their Environmental Impacts; High Performance CFD Computation; Performance of Multiphase Flow Systems; Wind Energy; Uncertainty Quantification in Flow Measurements and Simulations ◽

10.1115/fedsm2014-21634 ◽

2014 ◽

Author(s):

Mohammad Mehdi Tavakol ◽

Omid Abouali ◽

Mahmood Yaghoubi ◽

Goodarz Ahmadi

Keyword(s):

Pipe Flow ◽

Deposition Efficiency ◽

Hydrodynamic Forces ◽

Transport Processes ◽

Creeping Flow ◽

Spherical Particles ◽

Low Reynolds Number Flows ◽

Ellipsoidal Particles ◽

Deposition Fraction ◽

Laminar Pipe Flow

The physics of transport, deposition, detachment and reentrainment re-entrainment of particles suspended in a fluid are of great interests in many practical fluid engineering problems. For spherical particles, analysis of their translational motions is sufficient for a complete description of their transport processes. Prediction of transport and deposition of non-spherical particles, however, is more complicated due to the coupling of particle translational and rotational motions. Most studies related to dispersion of ellipsoidal particles used the traditional creeping flow formulations for hydrodynamic forces and torques. These formulations are valid for very low Reynolds number flows. In this study, dispersion and deposition of ellipsoidal particles in a fully developed laminar pipe flow are analyzed numerically using new correlations for hydrodynamic forces and torques. The deposition efficiency of the ellipsoidal particles in laminar pipe flow are calculated and the results are compared with other theoretical and numerical studies and good agreement is observed.

Download Full-text

Numerical Simulation of Particles Deposition in a Human Upper Airway

Advances in Mechanical Engineering ◽

10.1155/2014/207938 ◽

2014 ◽

Vol 6 ◽

pp. 207938 ◽

Cited By ~ 1

Author(s):

Debo Li ◽

Qisheng Xu ◽

Yaming Liu ◽

Yin Libao ◽

Jin Jun

Keyword(s):

Numerical Simulation ◽

Nasal Cavity ◽

Particle Deposition ◽

Geometric Model ◽

Particle Diameter ◽

Upper Airway ◽

Deposition Efficiency ◽

Particle Movement ◽

Scanned Images ◽

Les Model

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

Simulation on hydrodynamics of non-spherical particulate system using a drag coefficient correlation based on artificial neural network

Petroleum Science ◽

10.1007/s12182-019-00411-2 ◽

2019 ◽

Vol 17 (2) ◽

pp. 537-555

Author(s):

Sheng-Nan Yan ◽

Tian-Yu Wang ◽

Tian-Qi Tang ◽

An-Xing Ren ◽

Yu-Rong He

Keyword(s):

Neural Network ◽

Experimental Data ◽

Artificial Neural Network ◽

Drag Coefficient ◽

Fluidized Bed ◽

Spherical Particles ◽

Coefficient Corrélation ◽

Bubbling Fluidized Bed ◽

Simulation Results ◽

Artificial Neural

AbstractFluidization of non-spherical particles is very common in petroleum engineering. Understanding the complex phenomenon of non-spherical particle flow is of great significance. In this paper, coupled with two-fluid model, the drag coefficient correlation based on artificial neural network was applied in the simulations of a bubbling fluidized bed filled with non-spherical particles. The simulation results were compared with the experimental data from the literature. Good agreement between the experimental data and the simulation results reveals that the modified drag model can accurately capture the interaction between the gas phase and solid phase. Then, several cases of different particles, including tetrahedron, cube, and sphere, together with the nylon beads used in the model validation, were employed in the simulations to study the effect of particle shape on the flow behaviors in the bubbling fluidized bed. Particle shape affects the hydrodynamics of non-spherical particles mainly on microscale. This work can be a basis and reference for the utilization of artificial neural network in the investigation of drag coefficient correlation in the dense gas–solid two-phase flow. Moreover, the proposed drag coefficient correlation provides one more option when investigating the hydrodynamics of non-spherical particles in the gas–solid fluidized bed.

Download Full-text

A Numerical Investigation of Regional Fiber Deposition in a Realistic Nasal Cavity

Volume 1: Symposia, Parts A and B ◽

10.1115/fedsm2012-72368 ◽

2012 ◽

Author(s):

Alireza Dastan ◽

Omid Abouali ◽

Goodarz Ahmadi

Keyword(s):

Nasal Cavity ◽

Equations Of Motion ◽

Computer Code ◽

Spherical Particles ◽

Navier Stokes ◽

Continuity Equations ◽

Aspect Ratios ◽

Deposition Fraction ◽

Fiber Deposition ◽

Rotation Motion

In this paper, the motion and deposition of micro fibers in different regions of a realistic human nasal airway were studied using a computational modeling approach. The airflow field in the nasal cavity was simulated by solving the Navier-Stokes and continuity equations. The coupled translational and rotation motion of the fibers were analyzed by a Lagrangian approach assuming one-way coupling. The fibers were assumed to be ellipsoids and a computer code was developed for solving the coupled translational and rotational equations of motion of the ellipsoidal fiber. A large number of fibers were injected at the nostril and the deposition pattern and deposition fraction (DF) of the fibers in different regions of the nasal cavity were evaluated for different breathing rates, various fiber diameters and different fiber aspect ratios. The simulation results for ellipsoidal fibers obtained by solving the coupled translational and rotational equations were compared with those obtained by solving only the translational equations of equivalent spherical particles with a shape factor, which were used in some earlier works.

Download Full-text

BEHAVIORAL MODEL OF A LINEAR VOLTAGE STABILIZER IN THE SPICE LANGUAGE

CAD/EDA, MODELING AND SIMULATION IN MODERN ELECTRONICS: COLLECTION OF SCIENTIFIC PAPERS OF THE III INTERNATIONAL SCIENTIFIC AND PRACTICAL CONFERENCE ◽

10.30987/conferencearticle_5e028212469e90.44125818 ◽

2019 ◽

Author(s):

Aleksey Malahanov

Keyword(s):

Experimental Data ◽

Behavioral Model ◽

Voltage Stabilizer ◽

Static Mode ◽

Technical Description ◽

Simulation Results ◽

Chip Manufacturer ◽

Linear Voltage

A variant of the implementation of the behavioral model of a linear voltage stabilizer in the Spice language is presented. The results of modeling in static mode are presented. The simulation results are compared with experimental data and technical description of the chip manufacturer.

Download Full-text

Validating high level simulation results against experimental data and low level simulation

Proceedings of the 27th International Conference on Real-Time Networks and Systems - RTNS '19 ◽

10.1145/3356401.3356414 ◽

2019 ◽

Cited By ~ 1

Author(s):

David Griffin ◽

James Harbin ◽

Alan Burns ◽

Iain Bate ◽

Robert I. Davis ◽

...

Keyword(s):

Experimental Data ◽

Low Level ◽

Simulation Results ◽

High Level

Download Full-text

Realization of a fractional-order RLC circuit via constant phase element

International Journal of Dynamics and Control ◽

10.1007/s40435-021-00778-4 ◽

2021 ◽

Author(s):

Riccardo Caponetto ◽

Salvatore Graziani ◽

Emanuele Murgano

Keyword(s):

Experimental Data ◽

Carbon Black ◽

Fractional Order ◽

Constant Phase Element ◽

Polymeric Matrix ◽

Fractional Order Systems ◽

New Device ◽

Rlc Circuit ◽

Simulation Results

AbstractIn the paper, a fractional-order RLC circuit is presented. The circuit is realized by using a fractional-order capacitor. This is realized by using carbon black dispersed in a polymeric matrix. Simulation results are compared with the experimental data, confirming the suitability of applying this new device in the circuital implementation of fractional-order systems.

Download Full-text

Investigation of the Thickness Differential on the Formability of Aluminum Tailor Welded Blanks

Metals ◽

10.3390/met11060875 ◽

2021 ◽

Vol 11 (6) ◽

pp. 875

Author(s):

Jie Wu ◽

Yuri Hovanski ◽

Michael Miles

Keyword(s):

Experimental Data ◽

Finite Element ◽

Numerical Model ◽

Plastic Strain ◽

Finite Element Model ◽

Equivalent Plastic Strain ◽

Element Model ◽

Dome Height ◽

Tailor Welded Blanks ◽

Simulation Results

A finite element model is proposed to investigate the effect of thickness differential on Limiting Dome Height (LDH) testing of aluminum tailor-welded blanks. The numerical model is validated via comparison of the equivalent plastic strain and displacement distribution between the simulation results and the experimental data. The normalized equivalent plastic strain and normalized LDH values are proposed as a means of quantifying the influence of thickness differential for a variety of different ratios. Increasing thickness differential was found to decrease the normalized equivalent plastic strain and normalized LDH values, this providing an evaluation of blank formability.

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