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Cui X, Song W, Xue Y, Guan H, Zhang J, He X, Ma H, Lei M, Wang J, Li Y. Numerical investigations of the micro lunar dust particles deposition in the human oral respiratory airway. JOURNAL OF HAZARDOUS MATERIALS 2023; 448:130886. [PMID: 36716554 DOI: 10.1016/j.jhazmat.2023.130886] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2022] [Revised: 01/24/2023] [Accepted: 01/26/2023] [Indexed: 06/18/2023]
Abstract
Understanding the deposition of lunar dust (LD) particles in the human respiratory system is of great significance for protecting astronauts' health from the toxicity of lunar dust. A Euler-Lagrangian approach is adopted to track the LD particle motion in a human oral airway model. The investigations are conducted considering different inspiration rates and micro-particle sizes as well as different abnormal pressures and abnormal temperatures. It is found that 1) almost all the LD particles tend to enter the right lung rather than the left lung, especially in the upper right lobe; 2) at lower ambient pressure, fewer LD particles will deposit in the upper airway, while more particles will enter the lung; 3) at lower temperature, more LD particles are deposited in the upper airway, while fewer are deposited in the lung. In summary, the present work has shown that the LD particles have different depositing properties in the upper airway and the lung lobe regions up to the particle size, inspiration flow rate, temperature and pressure. It should pay more attentions on the upper airway and right upper lobe when it studies the toxicity of the lunar dust, and can't ignore the impact of the environmental temperature and pressure.
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Affiliation(s)
- Xinguang Cui
- School of Aerospace Engineering, Huazhong University of Science and Technology, Wuhan, China.
| | - Wei Song
- School of Aerospace Engineering, Huazhong University of Science and Technology, Wuhan, China
| | - Yuan Xue
- China Astronaut Research and Training Center, Beijing, China
| | - Hanxiong Guan
- Department of Radiology, Tongji Hospital, Huazhong University of Science and Technology, Wuhan, China
| | - Jinhua Zhang
- Department of Radiology, Tongji Hospital, Huazhong University of Science and Technology, Wuhan, China
| | - Xinxing He
- China Astronaut Research and Training Center, Beijing, China
| | - Honglei Ma
- China Astronaut Research and Training Center, Beijing, China
| | - Ming Lei
- China Astronaut Research and Training Center, Beijing, China
| | - Jintao Wang
- School of Aerospace Engineering, Huazhong University of Science and Technology, Wuhan, China
| | - Yichao Li
- School of Aerospace Engineering, Huazhong University of Science and Technology, Wuhan, China
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2
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Targeted drug delivery with polydisperse particle transport and deposition in patient-specific upper airway during inhalation and exhalation. Respir Physiol Neurobiol 2023; 308:103986. [PMID: 36396028 DOI: 10.1016/j.resp.2022.103986] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2022] [Revised: 10/16/2022] [Accepted: 11/07/2022] [Indexed: 11/16/2022]
Abstract
Identifying the deposition pattern of inhaled pharmaceutical aerosols in the human respiratory system and understanding the effective parameters in this process is vital for more efficient drug delivery to this region. This study investigated aerosol deposition in a patient-specific upper respiratory airway and determined the deposition fraction (DF) and pressure drop across the airway. An experimental setup was developed to measure the pressure drop in the same realistic geometry printed from the patient-specific geometry. The unsteady simulations were performed with a flow rate of 15 L/min and different particle diameters ranging from 2 to 30 µm. The results revealed significant flow circulation after the nasal valve in the upper and oropharynx regions, and a maximum local velocity observed in the nasopharynx. Transient cumulative deposition fraction showed that after 2 s of the simulation, all particles deposit or escape the computational domain. About 30 % of the injected large particles (dp ≥ 20 µm) deposited in the first 1 cm away from the nostril and more than 95 % deposited in the nasal airway before entering the oropharynx region. While almost 94 % deposition in trachea was composed of particles smaller than 5 µm. Approximately 20 % of inhaled fine particles (2-5 µm) deposited in the upper airway and the rest deposited in oropharynx, larynx and trachea.
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3
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Sun Q, Dong J, Zhang Y, Tian L, Tu J. Numerical modelling of micron particle inhalation in a realistic nasal airway with pediatric adenoid hypertrophy: A virtual comparison between pre- and postoperative models. Front Pediatr 2023; 11:1083699. [PMID: 36911037 PMCID: PMC9996336 DOI: 10.3389/fped.2023.1083699] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/29/2022] [Accepted: 01/26/2023] [Indexed: 02/25/2023] Open
Abstract
Adenoid hypertrophy (AH) is an obstructive condition due to enlarged adenoids, causing mouth breathing, nasal blockage, snoring and/or restless sleep. While reliable diagnostic techniques, such as lateral soft tissue x-ray imaging or flexible nasopharyngoscopy, have been widely adopted in general practice, the actual impact of airway obstruction on nasal airflow and inhalation exposure to drug aerosols remains largely unknown. In this study, the effects of adenoid hypertrophy on airflow and micron particle inhalation exposure characteristics were analysed by virtually comparing pre- and postoperative models based on a realistic 3-year-old nasal airway with AH. More specifically, detailed comparison focused on anatomical shape variations, overall airflow and olfactory ventilation, associated particle deposition in overall and local regions were conducted. Our results indicate that the enlarged adenoid tissue can significantly alter the airflow fields. By virtually removing the enlarged tissue and restoring the airway, peak velocity and wall shear stress were restored, and olfactory ventilation was considerably improved (with a 16∼63% improvement in terms of local ventilation speed). Furthermore, particle deposition results revealed that nasal airway with AH exhibits higher particle filtration tendency with densely packed deposition hot spots being observed along the floor region and enlarged adenoid tissue area. While for the postoperative model, the deposition curve was shifted to the right. The local deposition efficiency results demonstrated that more particles with larger inertia can be delivered to the targeted affected area following Adenoidectomy (Adenoid Removal). Research findings are expected to provide scientific evidence for adenoidectomy planning and aerosol therapy following Adenoidectomy, which can substantially improve present clinical treatment outcomes.
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Affiliation(s)
- Qinyuan Sun
- School of Engineering, RMIT University, Bundoora, VIC, Australia
| | - Jingliang Dong
- School of Engineering, RMIT University, Bundoora, VIC, Australia
| | - Ya Zhang
- Department of Otolaryngology Head and Neck Surgery, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, China
| | - Lin Tian
- School of Engineering, RMIT University, Bundoora, VIC, Australia
| | - Jiyuan Tu
- School of Engineering, RMIT University, Bundoora, VIC, Australia
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4
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Rahman MM, Zhao M, Islam MS, Dong K, Saha SC. Nanoparticle transport and deposition in a heterogeneous human lung airway tree: An efficient one path model for CFD simulations. Eur J Pharm Sci 2022; 177:106279. [PMID: 35985443 DOI: 10.1016/j.ejps.2022.106279] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2022] [Revised: 07/18/2022] [Accepted: 08/15/2022] [Indexed: 11/03/2022]
Abstract
Understanding nano-particle inhalation in human lung airways helps targeted drug delivery for treating lung diseases. A wide range of numerical models have been developed to analyse nano-particle transport and deposition (TD) in different parts of airways. However, a precise understanding of nano-particle TD in large-scale airways is still unavailable in the literature. This study developed an efficient one-path numerical model for simulating nano-particle TD in large-scale lung airway models. This first-ever one-path numerical approach simulates airflow and nano-particle TD in generations 0-11 of the human lung, accounting for 93% of the whole airway length. The one-path model enables the simulation of particle TD in many generations of airways with an affordable time. The particle TD of 5 nm, 10 nm and 20 nm particles is simulated at inhalation flow rates for two different physical activities: resting and moderate activity. It is found that particle deposition efficiency of 5 nm particles is 28.94% higher than 20 nm particles because of the higher dispersion capacity. It is further proved that the diffusion mechanism dominates the particle TD in generations 0-11. The deposition efficiency decreases with the increase of generation number irrespective of the flow rate and particle size. The effects of the particle size and flow rate on the escaping rate of each generation are opposite to the corresponding effects on the deposition rate. The quantified deposition and escaping rates at generations 0-11 provide valuable guidelines for drug delivery in human lungs.
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Affiliation(s)
- Md M Rahman
- School of Engineering, Design and Built Environment, Western Sydney University, Penrith, NSW 2751, Australia; Department of Mathematics, Faculty of Science, Islamic University, Kushtia 7003, Bangladesh
| | - Ming Zhao
- School of Engineering, Design and Built Environment, Western Sydney University, Penrith, NSW 2751, Australia.
| | - Mohammad S Islam
- School of Mechanical and Mechatronic Engineering, University of Technology Sydney, Ultimo, NSW 2007, Australia
| | - Kejun Dong
- School of Engineering, Design and Built Environment, Western Sydney University, Penrith, NSW 2751, Australia
| | - Suvash C Saha
- School of Mechanical and Mechatronic Engineering, University of Technology Sydney, Ultimo, NSW 2007, Australia
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5
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Numerical modeling of gas-solid two-phase flow in a plasma melting furnace. POWDER TECHNOL 2022. [DOI: 10.1016/j.powtec.2022.117967] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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6
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Dong J, Sun Q, Shang Y, Zhang Y, Tian L, Tu J. Numerical comparison of inspiratory airflow patterns in human nasal cavities with distinct age differences. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2022; 38:e3565. [PMID: 34913265 DOI: 10.1002/cnm.3565] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2021] [Revised: 11/07/2021] [Accepted: 12/11/2021] [Indexed: 06/14/2023]
Abstract
As a primary determinant of nasal physiological functions, the nasal morphology and its effects on the airflow dynamics have been extensively studied in literature. However, gross flow features reported in literature are mostly obtained from subjects at similar ages, while studies focusing on nasal subjects with distinct age differences are significantly less. To advance current understandings of nasal airflow dynamics in the context of age diversity, this study employed three anatomically accurate nasal cavity models with distinct age features (5-, 24- and 77-year-old models) and numerically compared the physiological nasal airflow fields within these nasal cavity models. To demonstrate the validity of the present numerical models, in vivo rhinomanometry measurement was conducted on the 24-year-old female nasal model, and key anatomical features and pressure-flow curves of all three models were compared with models with similar age features in literature work. Apart from results comparison based on conventional velocity flow fields and wall shear stress distributions, a method for quantifying flow partitions in confined airway spaces was developed to reveal the proportions of fractional flow that enters the olfactory region. Our results revealed dramatic intersubject discrepancies between considered nasal cavity models, especially for the fractional flow that enters the olfactory region. Specifically, the 5-year-old girl nasal model received the highest proportion of fractional flow, which accounts for 13.3% ~ 15% of overall inhalation flow rates under different activity levels. For the 24-year-old female model, on the contrary, the olfactory fractional flow was dramatically reduced (with a local to overall percentage around 4.3%-7.7%). Finally, for the elderly subject-77-year-old male model, minimum level of olfactory flux was observed with a local to overall percentage ranging between 3.1% and 4.9% for considered wide range of inhalation flow rates. Therefore, the local flow intersubject variation can reach nearly fourfold. The vast local flow difference is mainly due to the inherent anatomical features (e.g., immature nasal turbinate structure in the child model, the partial narrowing superior nasal valve in the elder model). The results may further lead to discrepant health effects associated with inhalation exposure to airborne particles.
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Affiliation(s)
- Jingliang Dong
- Mechanical and Automotive Engineering, School of Engineering, RMIT University, Bundoora, Victoria, Australia
| | - Qinyuan Sun
- Mechanical and Automotive Engineering, School of Engineering, RMIT University, Bundoora, Victoria, Australia
| | - Yidan Shang
- Mechanical and Automotive Engineering, School of Engineering, RMIT University, Bundoora, Victoria, Australia
| | - Ya Zhang
- Department of Otolaryngology Head and Neck Surgery, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, China
| | - Lin Tian
- Mechanical and Automotive Engineering, School of Engineering, RMIT University, Bundoora, Victoria, Australia
| | - Jiyuan Tu
- Mechanical and Automotive Engineering, School of Engineering, RMIT University, Bundoora, Victoria, Australia
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7
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Beni HM, Mortazavi H, Islam MS. Biomedical and biophysical limits to mathematical modeling of pulmonary system mechanics: a scoping review on aerosol and drug delivery. Biomech Model Mechanobiol 2022; 21:79-87. [PMID: 34725744 PMCID: PMC8559917 DOI: 10.1007/s10237-021-01531-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Accepted: 10/10/2021] [Indexed: 11/29/2022]
Abstract
Undoubtedly, the construction of the biomechanical geometry systems with the help of computer tomography (CT) and magnetic resonance imaging (MRI) has made a significant advancement in studying in vitro numerical models as accurately as possible. However, some simplifying assumptions in the computational studies of the respiratory system have caused errors and deviations from the in vivo actual state. The most important of these hypotheses is how to generate volume from the point cloud exported from CT or MRI images, not paying attention to the wall thickness and its effect in computational fluid dynamic method, statistical logic of aerosol trap in software; and most importantly, the viscoelastic effect of respiratory tract wall in living tissue pointed in the fluid-structure interaction method. So that applying the viscoelastic dynamic mesh effect in the form of the moving deforming mesh can be very effective in achieving more appropriate response quality. Also, changing the volume fraction of the pulmonary extracellular matrix constituents leads to changes in elastic modulus (storage modulus) and the viscous modulus (loss modulus) of lung tissue. Therefore, in the biomedical computational methods where the model wall is considered flexible, the viscoelastic properties of the texture must be considered correctly.
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Affiliation(s)
| | - Hamed Mortazavi
- Department of Biomedical Engineering, Arsanjan Branch, Islamic Azad University, Arsanjan, Iran
| | - Mohammad Saidul Islam
- School of Mechanical and Mechatronic Engineering, University of Technology Sydney (UTS), 15 Broadway, Ultimo, NSW, 2007, Australia
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8
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Liu X, Wang S, Du Y, Zheng M, Yang S, Wang H. CFD study of the thermochemical characteristics of mesoscale bubbles in a BFB gasifier. ADV POWDER TECHNOL 2021. [DOI: 10.1016/j.apt.2021.05.039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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9
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Shang Y, Tao Y, Dong J, He F, Tu J. Deposition features of inhaled viral droplets may lead to rapid secondary transmission of COVID-19. JOURNAL OF AEROSOL SCIENCE 2021; 154:105745. [PMID: 33456070 PMCID: PMC7796674 DOI: 10.1016/j.jaerosci.2021.105745] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Revised: 11/22/2020] [Accepted: 01/03/2021] [Indexed: 05/13/2023]
Abstract
Inhaled viral droplets may immediately be expelled and cause an escalating re-transmission. Differences in the deposition location of inhaled viral droplets may have a direct impact on the probability of virus expelling. This study develops a numerical model to estimate the region-specific deposition fractions for inhalable droplets (1-50 μ m) in respiratory airways. The results identified a higher deposition fraction in the upper airways than the lower airways. Particularly for droplets larger than 10 μ m, the relatively high deposition fraction in the oral/laryngeal combined region warns of its easy transmission through casual talking/coughing. Moreover, considering droplet sizes' effect on virus loading capacity, we built a correlation model to quantify the potential of virus expelling hazards, which suggests an amplified cascade effect on virus transmission on top of the existing transmission mechanism. It therefore highlights the importance of considering the instant expelling possibilities from inhaled droplets, and also implies potentials in restricting a rapid secondary transmission by measures that can lower down droplet deposition in the upper airways.
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Affiliation(s)
- Yidan Shang
- College of Air Transportation, Shanghai University of Engineering Science, Shanghai 201620, China
| | - Yao Tao
- School of Engineering, RMIT University, PO Box 71, Bundoora, VIC 3083, Australia
| | - Jingliang Dong
- School of Engineering, RMIT University, PO Box 71, Bundoora, VIC 3083, Australia
| | - Fajiang He
- College of Air Transportation, Shanghai University of Engineering Science, Shanghai 201620, China
| | - Jiyuan Tu
- School of Engineering, RMIT University, PO Box 71, Bundoora, VIC 3083, Australia
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10
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Dong J, Ma J, Tian L, Inthavong K, Ito K, Tu J. Numerical analysis of nanoparticle transport and deposition in a cynomolgus monkey nasal passage. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2021; 37:e3414. [PMID: 33205913 DOI: 10.1002/cnm.3414] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Revised: 10/13/2020] [Accepted: 11/15/2020] [Indexed: 06/11/2023]
Abstract
Environmental exposure to toxic agents is commonly encountered by occupational and residential populations. However, in vivo exposure data in human subjects is limited by measurement and ethical restrictions. Monkey represents a suitable surrogate for human exposure studies, but the particle transport and deposition features in monkey airways are still not well understood. As a response to this research challenge, this paper presents a virtual exposure study that numerically investigated the nanoparticle transport process through a realistic cynomolgus monkey nasal airway. Particles with size of 1 nm to 1 μm were considered and the transport process was modelled by the Lagrangian discrete phase model. Overall and local deposition as well as particle dispersion along the airway were examined by using a variety of non-dimensional parameters including combined diffusion parameter, deposition enhancement factor and particle flux enhancement factor. Consistent deposition patterns were observed in present and literature nasal models. Most particles tended to pass the nasal airway through certain spatial regions, including the middle section of the nasal valve, the lower half of the middle coronal plane, and the central regions of the choana. While naturally inhaled nanoparticles can hardly be delivered to the olfactory region as it is located apart from the mainstream with high particle flux. Research findings provide insight into nanoparticle inhalation exposure characteristics in the monkey airway and can contribute in formulating data extrapolation schemes between monkey and human airways.
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Affiliation(s)
- Jingliang Dong
- Indoor Environment Engineering Research Center of Fujian Province, College of Ecological Environment and Urban Construction, Fujian University of Technology, Fuzhou, China
- Mechanical & Automotive Engineering, School of Engineering, RMIT University, Bundoora, Victoria, Australia
| | - Jiawei Ma
- Mechanical & Automotive Engineering, School of Engineering, RMIT University, Bundoora, Victoria, Australia
| | - Lin Tian
- Mechanical & Automotive Engineering, School of Engineering, RMIT University, Bundoora, Victoria, Australia
| | - Kiao Inthavong
- Mechanical & Automotive Engineering, School of Engineering, RMIT University, Bundoora, Victoria, Australia
| | - Kazuhide Ito
- Department of Advanced Environmental Science and Engineering, Faculty of Engineering Sciences, Kyushu University, Kyushu, Japan
| | - Jiyuan Tu
- Mechanical & Automotive Engineering, School of Engineering, RMIT University, Bundoora, Victoria, Australia
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11
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Shang Y, Inthavong K, Qiu D, Singh N, He F, Tu J. Prediction of nasal spray drug absorption influenced by mucociliary clearance. PLoS One 2021; 16:e0246007. [PMID: 33507973 PMCID: PMC7842989 DOI: 10.1371/journal.pone.0246007] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Accepted: 01/12/2021] [Indexed: 12/11/2022] Open
Abstract
Evaluation of nasal spray drug absorption has been challenging because deposited particles are consistently transported away by mucociliary clearance during diffusing through the mucus layer. This study developed a novel approach combining Computational Fluid Dynamics (CFD) techniques with a 1-D mucus diffusion model to better predict nasal spray drug absorption. This integrated CFD-diffusion approach comprised a preliminary simulation of nasal airflow, spray particle injection, followed by analysis of mucociliary clearance and drug solute diffusion through the mucus layer. The spray particle deposition distribution was validated experimentally and numerically, and the mucus velocity field was validated by comparing with previous studies. Total and regional drug absorption for solute radius in the range of 1 − 110nm were investigated. The total drug absorption contributed by the spray particle deposition was calculated. The absorption contribution from particles that deposited on the anterior region was found to increase significantly as the solute radius became larger (diffusion became slower). This was because the particles were consistently moved out of the anterior region, and the delayed absorption ensured more solute to be absorbed by the posterior regions covered with respiratory epithelium. Future improvements in the spray drug absorption model were discussed. The results of this study are aimed at working towards a CFD-based integrated model for evaluating nasal spray bioequivalence.
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Affiliation(s)
- Yidan Shang
- College of Air Transportation, Shanghai University of Engineering Science, Shanghai, China.,School of Engineering, RMIT University, Bundoora, VIC, Australia
| | - Kiao Inthavong
- School of Engineering, RMIT University, Bundoora, VIC, Australia
| | - Dasheng Qiu
- Department of Nuclear medicine (Positron Emission Tomography/Computed Tomography), Hubei Cancer Hospital, Wuhan, Hubei, China
| | - Narinder Singh
- Department of Otolaryngology Head and Neck Surgery, Westmead Hospital, Sydney, Australia.,School of Medicine, University of Sydney, Sydney, Australia
| | - Fajiang He
- College of Air Transportation, Shanghai University of Engineering Science, Shanghai, China
| | - Jiyuan Tu
- School of Engineering, RMIT University, Bundoora, VIC, Australia
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12
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Calmet H, Inthavong K, Owen H, Dosimont D, Lehmkuhl O, Houzeaux G, Vázquez M. Computational modelling of nasal respiratory flow. Comput Methods Biomech Biomed Engin 2020; 24:440-458. [PMID: 33175592 DOI: 10.1080/10255842.2020.1833865] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
CFD has emerged as a promising diagnostic tool for clinical trials, with tremendous potential. However, for real clinical applications to be useful, overall statistical findings from large population samples (e.g., multiple cases and models) are needed. Fully resolved solutions are not a priority, but rather rapid solutions with fast turn-around times are desired. This leads to the issue of what are the minimum modelling criteria for achieving adequate accuracy in respiratory flows for large-scale clinical applications, with a view to rapid turnaround times. This study simulated a highly-resolved solution using the large eddy simulation (LES) method as a reference case for comparison with lower resolution models that included larger time steps and no turbulence modelling. Differences in solutions were quantified by pressure loss, flow resistance, unsteadiness, turbulence intensity, and hysteresis effects from multiple cycles. The results demonstrated that sufficient accuracy could be achieved with lower resolution models if the mean flow was considered. Furthermore, to achieve an established transient result unaffected by the initial start-up quiescent effects, the results need to be taken from at least the second respiration cycle. It was also found that the exhalation phase exhibited strong turbulence. The results are expected to provide guidance for future modelling efforts for clinical and engineering applications requiring large numbers of cases using simplified modelling approaches.
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Affiliation(s)
- H Calmet
- Department of Computer Applications in Science and Engineering, Barcelona Supercomputing Center (BSC-CNS), Barcelona, Spain
| | - K Inthavong
- Mechanical & Automotive Engineering, School of Engineering, RMIT University, Melbourne, Australia
| | - H Owen
- Department of Computer Applications in Science and Engineering, Barcelona Supercomputing Center (BSC-CNS), Barcelona, Spain
| | - D Dosimont
- Department of Computer Applications in Science and Engineering, Barcelona Supercomputing Center (BSC-CNS), Barcelona, Spain
| | - O Lehmkuhl
- Department of Computer Applications in Science and Engineering, Barcelona Supercomputing Center (BSC-CNS), Barcelona, Spain
| | - G Houzeaux
- Department of Computer Applications in Science and Engineering, Barcelona Supercomputing Center (BSC-CNS), Barcelona, Spain
| | - M Vázquez
- Department of Computer Applications in Science and Engineering, Barcelona Supercomputing Center (BSC-CNS), Barcelona, Spain
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13
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Vachhani S, Kleinstreuer C. Comparison of micron- and nano-particle transport in the human nasal cavity with a focus on the olfactory region. Comput Biol Med 2020; 128:104103. [PMID: 33220592 DOI: 10.1016/j.compbiomed.2020.104103] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Revised: 10/12/2020] [Accepted: 10/31/2020] [Indexed: 12/20/2022]
Abstract
Intranasal administration of drugs serves as a promising, noninvasive option for the treatment of various disorders of the central nervous system and upper respiratory tract. Predictive, ie, realistic and accurate, particle tracking in the human nasal cavities is an essential step to achieve these goals. The major factors affecting aerosol transport and deposition are the inhalation flowrate, the particle characteristics, and the nasal airway geometry. In vivo and in vitro studies using nasal cavity casts provide realistic images regarding particle-deposition pattern. Computational Fluid-Particle Dynamics (CF-PD) studies can offer a flexible, detailed and cost effective solution to the problem of direct drug delivery. The open-source software OpenFOAM was employed to conduct, after model validation, laminar and turbulent fluid-particle dynamics simulations for representative nasal cavities. Specifically, micron particles and nanoparticles were both individually tracked for different steady airflow rates to determine sectional deposition efficiencies. For micron particles, inertial forces were found to be the dominating factor, resulting in higher deposition for larger particles, mainly due to impaction. In contrast, diffusional effects are more important for nanoparticles. With a focus on the olfactory region, the detailed analysis of sectional deposition concentrations, considering a wide range of particle diameters, provide new physical insight to the particle dynamics inside human nasal cavities. The laminar/turbulent Euler-Lagrange modelling approach for simulating the fate of nanoparticles form a foundation for future studies focusing on targeted drug delivery. A major application would be direct nanodrug delivery to the olfactory region to achieve large local concentrations for possible migration across the blood-brain-barrier.
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Affiliation(s)
- Shantanu Vachhani
- Department of Mechanical and Aerospace Engineering, North Carolina State University, United States
| | - Clement Kleinstreuer
- Department of Mechanical and Aerospace Engineering, North Carolina State University, United States.
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14
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Yang S, Wang S. Shape Effect of the Riser Cross Section on the Full-Loop Hydrodynamics of a Three-Dimensional Circulating Fluidized Bed. ACS OMEGA 2020; 5:5784-5795. [PMID: 32226858 PMCID: PMC7097897 DOI: 10.1021/acsomega.9b03903] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Accepted: 03/02/2020] [Indexed: 05/12/2023]
Abstract
In this work, numerical simulation is carried out in a three-dimensional full-loop pilot-scale circulating fluidized bed to explore the shape effect of the riser cross section on the typical flow characteristics of the bed via the multiphase particle-in-cell (MP-PIC) method. The gas and solid phases are modeled with the large eddy simulation and Newton's law of motion in the Eulerian and Lagrangian frameworks, respectively. The proposed model has been well validated with experimental data, followed by evaluating the typical core-annulus structure and the nonuniformity of the solid phase distributed along the radial and axial directions of the riser. Then, the particle-scale information of the solid phase distributed in different parts of the system is explored. The results demonstrate that (i) the square riser gives rise to a higher solid inventory in the standpipe owing to the stronger circulation intensity; (ii) the thickness of the solid back-mixing layer reduces along the riser height; the solid back-mixing tends to concentrate in the four corners, while it is not obvious near the sidewalls of the square riser; and (iii) nonuniform distribution of the particle-scale information of the solid phase (e.g., mass, flux, drag force, and slip velocity) can be observed. The square riser gives rise to comparatively more uniform axial mass distribution, a larger rising solid flux, larger horizontal transportation velocity between the core and annulus regions, and a larger horizontal dispersion coefficient in the riser, as compared with the corresponding ones in the circular riser.
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Affiliation(s)
- Shiliang Yang
- State Key Laboratory of Complex Nonferrous Metal Resources Clean Utilization, Kunming University of Science and Technology, Kunming 650093, P. R. China
| | - Shuai Wang
- School of Chemical Engineering, University of New South Wales, Sydney, NSW 2052, Australia
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15
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Numerical and Experimental Analysis of Inhalation Airflow Dynamics in a Human Pharyngeal Airway. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2020; 17:ijerph17051556. [PMID: 32121245 PMCID: PMC7084933 DOI: 10.3390/ijerph17051556] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/10/2020] [Revised: 02/25/2020] [Accepted: 02/26/2020] [Indexed: 11/17/2022]
Abstract
This paper presents a computational and experimental study of steady inhalation in a realistic human pharyngeal airway model. To investigate the intricate fluid dynamics inside the pharyngeal airway, the numerical predicted flow patterns are compared with in vitro measurements using Particle Image Velocimetry (PIV) approach. A structured mesh with 1.4 million cells is used with a laminar constant flow rate of 10 L/min. PIV measurements are taken in three sagittal planes which showed flow acceleration after the pharynx bend with high velocities in the posterior pharyngeal wall. Computed velocity profiles are compared with the measurements which showed generally good agreements with over-predicted velocity distributions on the anterior wall side. Secondary flow patterns on cross-sectional slices in the transverse plane revealed vortices posterior of pharynx and a pair of secondary flow vortexes due to the abrupt cross-sectional area increase. Finally, pressure and flow resistance analysis demonstrate that greatest pressure occurs in the superior half of the airway and maximum in-plane pressure variation is observed at the velo-oropharynx junction, which expects to induce a high tendency of airway collapse during inhalation. This study provides insights of the complex fluid dynamics in human pharyngeal airway and can contribute to a reliable approach to assess the probability of flow-induced airway collapse and improve the treatment of obstructive sleep apnea.
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Xu X, Wu J, Weng W, Fu M. Investigation of inhalation and exhalation flow pattern in a realistic human upper airway model by PIV experiments and CFD simulations. Biomech Model Mechanobiol 2020; 19:1679-1695. [PMID: 32026145 DOI: 10.1007/s10237-020-01299-3] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Accepted: 01/21/2020] [Indexed: 11/30/2022]
Abstract
In this study, flow field characteristics in the trachea region in a realistic human upper airway model were firstly measured by particle image velocimetry (PIV) in the air under three constant inhalation and exhalation conditions: 36 L/min, 64 L/min and 90 L/min, representing flow rates of 18 L/min, 32 L/min and 45 L/min in real human airway (the model was twice the size of a human airway). Computational fluid dynamics (CFD) analyses were performed on four turbulence models, with boundary conditions corresponding to the PIV experiments. The effects of flow rates and breathing modes on the airflow patterns were investigated. The CFD prediction results were compared with the PIV measurements and showed relatively good agreement in all cases. During inhalation, the higher the flow rates, the less significant the "glottal jet" phenomenon, and the smaller the area of the separation zone. The air in the nasal inhalation condition accelerated more dramatically after glottis. The SST-Transition model was the best choice for predicting inhalation velocity profiles. For exhalation condition, the maximum velocity was much smaller than that during inhalation due to the more uniform flow field. The exhalation flow rates and breathing modes had little effect on the flow characteristics in the trachea region. The RNG k - ε model and SST k - ω model were recommended to simulate the flow field in the respiratory tract during exhalation.
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Affiliation(s)
- Xiaoyu Xu
- Institute of Public Safety Research, Department of Engineering Physics, Tsinghua University, Beijing, 100084, People's Republic of China.,Beijing Key Laboratory of City Integrated Emergency Response Science, Tsinghua University, Beijing, 100084, China
| | - Jialin Wu
- Institute of Public Safety Research, Department of Engineering Physics, Tsinghua University, Beijing, 100084, People's Republic of China.,Beijing Key Laboratory of City Integrated Emergency Response Science, Tsinghua University, Beijing, 100084, China
| | - Wenguo Weng
- Institute of Public Safety Research, Department of Engineering Physics, Tsinghua University, Beijing, 100084, People's Republic of China. .,Beijing Key Laboratory of City Integrated Emergency Response Science, Tsinghua University, Beijing, 100084, China.
| | - Ming Fu
- Hefei Institute for Public Safety Research, Tsinghua University, Hefei, 320601, Anhui Province, China
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Yang S, Wang H, Wei Y, Hu J, Chew JW. Flow dynamics of binary mixtures of non-spherical particles in the rolling-regime rotating drum. POWDER TECHNOL 2020. [DOI: 10.1016/j.powtec.2019.10.110] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Yan Y, Li X, Tu J, Feng P, Zhang J. Characterisation and analysis of indoor tornado for contaminant removal and emergency ventilation. BUILDING AND ENVIRONMENT 2019; 164:106345. [PMID: 32287992 PMCID: PMC7116992 DOI: 10.1016/j.buildenv.2019.106345] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Revised: 08/02/2019] [Accepted: 08/12/2019] [Indexed: 06/11/2023]
Abstract
As an essential emergency management strategy, innovative emergency ventilation schemes that can quickly remove infectious and fatal contaminants without further spreading are highly demanded for public and commercial buildings. This study numerically investigated a vortex flow driven ventilation in a model room to explore the dynamic characteristics and 3D visualisation of vortex-driven indoor tornados. Four approaches to identify the core region of the indoor tornado were developed and compared against each other. By successfully capturing the continuously changing centre of the vortex and significant core region size variations at different heights, the swirl vector method was recommended as a quantifiable approach to identify the core region of indoor tornados. The numerical outcomes also revealed a strong connection between the lift angle, vortex intensity, overall size of indoor tornado and maximum size of core region. The best contaminants control and removal was achieved at lift angle of 20° in this study and an optimum lift angle ranging from 10° to 20° was recommended for future study.
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Affiliation(s)
- Yihuan Yan
- School of Engineering, RMIT University, PO Box 71, Bundoora, VIC, 3083, Australia
| | - Xiangdong Li
- School of Engineering, RMIT University, PO Box 71, Bundoora, VIC, 3083, Australia
| | - Jiyuan Tu
- School of Engineering, RMIT University, PO Box 71, Bundoora, VIC, 3083, Australia
- Key Laboratory of Ministry of Education for Advanced Reactor Engineering and Safety, Institute of Nuclear and New Energy Technology, Tsinghua University, PO Box 1021, Beijing, 100086, China
| | - Peijie Feng
- School of Engineering, RMIT University, PO Box 71, Bundoora, VIC, 3083, Australia
| | - Jiaqiao Zhang
- School of Engineering, RMIT University, PO Box 71, Bundoora, VIC, 3083, Australia
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