Particle deposition in human airways—An overview

1995 ◽  
Vol 26 (1) ◽  
pp. 156
Author(s):  
Chiu-Sen Wang
Keyword(s):  
Particle Deposition ◽  
Human Airways

Numerical assessment of natural respiration and particles deposition in the computed tomography scan airway with a glomus tumour

2021 ◽  
pp. 095440892110240
Author(s):  
Digamber Singh
Keyword(s):  
Computed Tomography ◽  
Respiratory Tract ◽  
Particle Deposition ◽  
Flow Characteristics ◽  
Glomus Tumour ◽  
Computed Tomography Scan ◽  
Human Respiratory Tract ◽  
Airflow Pattern ◽  
Human Airways ◽  
Tomography Scan

The human respiratory tract has a complex airflow pattern. If any obstruction is present in the airways, it will change the airflow pattern and deposit particles inside the airways. This is the concern of breath quality (inspired air), and it is decreasing due to the unplanned production of material goods. This is a primary cause of respiratory illness (asthma, cancer, etc.). Therefore, it is important to identify the flow characteristics in the human airways and airways with a glomus tumour with particle deposition. A numerical diagnosis is presented with an asymmetric unsteady-state light breathing condition (10 l/min). An in vitro human respiratory tract model has been reconstructed using computed tomography scan techniques and an artificial glomus tumour developed 2 cm above a carina on the posterior wall of the trachea. The transient flow characteristics are numerically simulated with a realizable (low Reynolds number) k–ɛ turbulence model. The flow disturbance is captured around the tumour, which influenced the upstream and downstream of the flow. The flow velocity pattern, wall shear stress and probable area of inflammation (hotspot) due to suspended particle deposition are determined, which may assist doctors more effectively in aerosol therapy and prosthetics of human airways illness.

scholarly journals Deposition of Smoke Particles in Human Airways with Realistic Waveform

Atmosphere ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 912
Author(s):  
Akshoy Ranjan Paul ◽  
Firoz Khan ◽  
Anuj Jain ◽  
Suvash Chandra Saha
Keyword(s):  
Oral Cavity ◽  
Cigarette Smoke ◽  
Particle Deposition ◽  
Transient Flow ◽  
Fine Particles ◽  
Geometric Model ◽  
Pulmonary Complications ◽  
Discrete Phase Model ◽  
Smoke Particle ◽  
Human Airways

Exposure to toxic particles from smoke generated either from bush fire, stable burning, or direct smoking is very harmful to our health. The tiny particles easily penetrate deep into the lungs after exposure and damage the airways. Tobacco smoking causes the direct emission of 2.6 million tons of CO2 and 5.2 million tons of methane annually into the atmosphere. Nevertheless, it is one of the significant contributors to various respiratory diseases leading to lung cancer. These particles’ deposition in the human airway is computed in the present article for refining our understanding of the adverse health effects due to smoke particle inhalation, especially cigarette smoke. Until recently, little work has been reported to account for the transient flow pattern of cigarette smoking. Consideration of transient flow may change the deposition pattern of the particle. A high-resolution CT scan image of the respiratory tract model consisting of the oral cavity, throat, trachea, and first to sixth generations of the lungs helps predict cigarette smoke particle (CSP) deposition. With the same scan, a realistic geometric model of the human airways of an adult subject is used to simulate the transport of air and particle. The CSP deposition is determined at different locations from the oral cavity to the sixth generation of the bronchi. In addition, an unsteady breathing curve indicative of realistic smoking behavior is utilized to represent the breathing conditions accurately. The discrete phase model (DPM) technique is used to determine smoke particle deposition in the human airways. It is found that the deposition increases with the size of the smoke particle. Particles tend to deposit in the oral cavity around the bifurcation junction of the airways. The deposition fraction of CSP with the realistic waveform of smoking is found to be smaller compared to that during the stable flow condition. It is also observed that the fine particles (0.1–1.0 micron) escape to lower generations, leading to higher deposition of fine particles in the deeper airways. The outcome of the study is helpful for understanding smoke-related pulmonary complications.

Numerical simulation of particle deposition in obstructive human airways

2012 ◽  
Vol 19 (3) ◽  
pp. 609-614 ◽  
Author(s):  
Cui-yun Ou ◽  
Qi-hong Deng ◽  
Wei-wei Liu
Keyword(s):  
Numerical Simulation ◽  
Particle Deposition ◽  
Human Airways

scholarly journals Risk Assessment of Infection by Airborne Droplets and Aerosols at Different Levels of Cardiovascular Activity

2021 ◽  
Author(s):  
Jana Wedel ◽  
Paul Steinmann ◽  
Mitja Štrakl ◽  
Matjaž Hriberšek ◽  
Jure Ravnik
Keyword(s):  
Particle Size ◽  
Particle Deposition ◽  
Control Strategies ◽  
Disease Onset ◽  
Aerosol Deposition ◽  
Size Distributions ◽  
Cardiovascular Activity ◽  
Particle Size Distributions ◽  
General Observation ◽  
Human Airways

AbstractSince end of 2019 the COVID-19 pandemic, caused by the SARS-CoV-2 virus, is threatening humanity. Despite the fact that various scientists across the globe try to shed a light on this new respiratory disease, it is not yet fully understood. Unlike many studies on the geographical spread of the pandemic, including the study of external transmission routes, this work focuses on droplet and aerosol transport and their deposition inside the human airways. For this purpose, a digital replica of the human airways is used and particle transport under various levels of cardiovascular activity in enclosed spaces is studied by means of computational fluid dynamics. The influence of the room size, where the activity takes place, and the aerosol concentration is studied. The contribution aims to assess the risk of various levels of exercising while inhaling infectious pathogens to gain further insights in the deposition behavior of aerosols in the human airways. The size distribution of the expiratory droplets or aerosols plays a crucial role for the disease onset and progression. As the size of the expiratory droplets and aerosols differs for various exhaling scenarios, reported experimental particle size distributions are taken into account when setting up the environmental conditions. To model the aerosol deposition we employ $$\text{OpenFOAM}$$ OpenFOAM  by using an Euler-Lagrangian frame including Reynolds-Averaged Navier–Stokes resolved turbulent flow. Within this study, the effects of different exercise levels and thus breathing rates as well as particle size distributions and room sizes are investigated to enable new insights into the local particle deposition in the human airway and virus loads. A general observation can be made that exercising at higher levels of activity is increasing the risk to develop a severe cause of the COVID-19 disease due to the increased aerosolized volume that reaches into the lower airways, thus the knowledge of the inhaled particle dynamics in the human airways at various exercising levels provides valuable information for infection control strategies.

A New Drift-Flux Model for Particle Transport and Deposition in Human Airways

2005 ◽  
Vol 128 (1) ◽  
pp. 97-105 ◽  
Author(s):  
J. B. Wang ◽  
Alvin C. K. Lai
Keyword(s):  
Particle Deposition ◽  
Electrostatic Force ◽  
Deposition Efficiency ◽  
Laminar Flows ◽  
Brownian Diffusion ◽  
Straight Tube ◽  
Drift Flux Model ◽  
Drift Flux ◽  
Flux Model ◽  
Human Airways

Particle deposition and transport in human airways is frequently modeled numerically by the Lagrangian approach. Current formulations of such models always require some ad hoc assumptions, and they are computationally expensive. A new drift-flux model is developed and incorporated into a commercial finite volume code. Because it is Eulerian in nature, the model is able to simulate particle deposition patterns, distribution and transport both spatially and temporally. Brownian diffusion, gravitational settling, and electrostatic force are three major particle deposition mechanisms in human airways. The model is validated against analytical results for three deposition mechanisms in a straight tube prior to applying the method to a single bifurcation G3-G4. Two laminar flows with Reynolds numbers 500 and 2000 are simulated. Particle concentration contour, deposition pattern, and enhancement factor are evaluated. To demonstrate how the diffusion and settling influence the deposition and transport along the bifurcation, particle sizes from 1nmto10μm are studied. Different deposition mechanisms can be combined into the mass conversation equation. Combined deposition efficiency for the three mechanisms simultaneously was evaluated and compared with two commonly used empirical expressions.

Flow and Particle Deposition in Asymmetric Human Airways

2006 ◽  
Author(s):  
L. Tian ◽  
G. Ahmadi ◽  
P. K. Hopke ◽  
Y.-S. Cheng
Keyword(s):  
Particle Transport ◽  
Particle Deposition ◽  
Transport Model ◽  
Tracheobronchial Tree ◽  
Upper Airways ◽  
Reynolds Stress Transport Model ◽  
Airflow Field ◽  
Human Airways ◽  
Upper Thoracic ◽  
Drug Delivery Devices

Transport and deposition of particles in human upper thoracic airways is important to understand their toxicology and the effect of exposure to environmental particulate matter as well as in the design of inhalation drug delivery devices. In the past, limited studies have employed 3-D asymmetric models to study the airflow through human lung, although tracheobronchial branching is generally asymmetric. Also limited work has been devoted to the study of particle deposition in upper airways where turbulence is important to particle depositions. It is also known that the asymmetry of the airways has a profound effect on the airflow fields and particle transport and deposition. The present study is concerned with providing a more accurate computational model for lung deposition. A realistic 3-D asymmetric bifurcation representation of human upper tracheobronchial tree has been developed to simulate the airflow field characterizing the inspiratory flow conditions using a turbulence Reynolds stress transport model. A Lagrangian particle trajectory analysis was also used for analyzing particle transport and deposition patterns in the upper tracheobronchial tree.

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