Numerical simulation of welding fume lung dosimetry

Zhao, Jianan; Feng, Yu; Bezerra, Marcio; Wang, Jun; Sperry, Ted

doi:10.1016/j.jaerosci.2019.05.006

Cited by 30 publications

(17 citation statements)

References 58 publications

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“…It is worth mentioning that the CFPD model and the in-house codes have been well validated in previous publications (Chen et al, 2017;Yu Feng et al, 2018;Haghnegahdar et al, 2019;Zhao et al, 2019). The validations with benchmark experimental data in previous publications include:…”

Section: Model Validationsmentioning

confidence: 88%

“…1). The two virtual humans are identical to the model used in the previous study (Zhao et al, 2019). The mouth opening is created for the virtual human on the left with a hydraulic diameter equal to 10 mm.…”

Section: Geometry and Computational Meshmentioning

confidence: 99%

“…To predict the transport, size change, and deposition of the emitted virus-laden droplets generated from a cough, the well-validated Euler-Lagrange based multiphase flow model has been employed (Haghnegahdar et al, 2019;Zhao et al, 2019). The governing equations are listed as follows:…”

Section: Governing Equationsmentioning

confidence: 99%

“…(1) Use large eddy simulation (LES) instead of RANS model combined with overset mesh method to model the turbulence ambient airflow fields waked by the walking motion of human (Edge, Paterson, & Settles, 2005;Settles, 2006); (2) Consider the atomization and coagulation between liquid bulk and droplets using the hybrid volume of fluid (VOF)-discrete phase model (DPM) method (Balasubramanian, Kumar, Nakod, Schütze, & Rajan, 2020;Xiao, Liu, & Liu, 2019); (3) Perform extensive parametric analysis to seek for other vital factors that can influence the airborne transmission of the SARS-CoV-2 laden droplets, e.g., droplet size distributions generated by different emission activities (e.g., sneeze (Hassani & Khorramymehr, 2019), vigorous breath, and loud speech (Asadi et al, 2019)), human heights, and emitted jet waveforms, jet spread angle variability (Gupta, Lin, & Chen, 2009), mouth opening variabilities during the emission, and environmental temperature; and (4) Integrate the human respiratory system with the virtual human body shell to simulate the resultant transport and deposition of COVID-19 virus-laden droplets in airways and the stimulated immune system responses using established multiscale models (Haghnegahdar et al, 2019;Kuga et al, 2020;Zhao et al, 2019) The future work will be done continuously to enhance the fundamental understanding of the airborne transmission of SARS-CoV-2 for better preparations against the post-pandemic period with the high possibility of resurgence (Kissler et al, 2020).…”

Section: Limitations Of the Study And Future Workmentioning

confidence: 99%

“…This study employed a well-validated computational fluid-particle dynamics (CFPD) model (Chen, Feng, Zhong, & Kleinstreuer, 2017;Feng, Kleinstreuer, Castro, & Rostami, 2016;Y Feng, Kleinstreuer, & Rostami, 2015;Yu Feng et al, 2018;Haghnegahdar, Zhao, & Feng, 2019;Zhao, Feng, Bezerra, Wang, & Sperry, 2019) with the modeling capability of predicting droplet size changes due to condensation and evaporation to simulate SARS-CoV-2-laden droplets transmission between two virtual humans, to quantify the wind and RH effects on the droplet deposition on the human body and head region, and provide guidance on fine-tuning the social distancing policy based on environmental parameters. Specifically, using benchmark data of cough aerosol characterizations (Duguid, 1946;, this study simulated the transient transport, condensation/evaporation, and deposition of SARS-CoV-2 laden droplets emitted by a cough between two virtual humans with different environmental wind velocities.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Influence of wind and relative humidity on the social distancing effectiveness to prevent COVID-19 airborne transmission: A numerical study

Feng

Marchal²,

Sperry

et al. 2020

Journal of Aerosol Science

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350

356

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It has been confirmed that the coronavirus disease 2019 (COVID-19) can transmit through droplets created when an infected human coughs or sneezes. Accordingly, 1.83-m (6-feet) social distancing is advised to reduce the spread of the disease among humans. This is based on the assumption that no air circulation exists around people. However, it is not well investigated whether the ambient wind and relative humidity (RH) will cause SARS-CoV-2 laden droplets to transport farther in the air, and make the current social distancing policy insufficient. To provide evidence and insight into the "social distancing" guidelines, a validated computational fluidparticle dynamics (CFPD) model was employed to simulate the transient transport, condensation/evaporation, and deposition of SARS-CoV-2 laden droplets emitted by coughs, with different environmental wind velocities and RHs. Initial droplet diameters range from 2 to 2000 μm, and the wind velocities range from 0 to 16 km/h, representing different wind forces from calm air to moderate breeze. The comparison between a steady-state wind and a gust with a constant frequency has also been performed. Ambient RHs are 40% and 99.5%. The distances between the two virtual humans are 1.83 m and 3.05 m (6 feet and 10 feet). The facial covering effect on reducing the airborne transmission of the cough droplets has also been evaluated. Numerical results indicate that the ambient wind will enhance the complexity of the secondary flows with recirculation between the two virtual humans. Microdroplets follow the airflow streamlines well and deposit on both human bodies and head regions, even with the 3.05-m (10-feet) separation distance. The rest of the microdroplets can transport in the air farther than 3.05 m (10 feet) due to wind convection, causing a potential health risk to nearby people. High RH will increase the droplet sizes due to the hygroscopic growth effect, which increases the deposition fractions on both humans and the ground. With the complex environmental wind and RH conditions, the 6feet social distancing policy may not be sufficient to protect the inter-person aerosol transmission, since the suspending micro-droplets were influenced by convection effects and can transport from the human coughs/sneezes to the other human in less than 5 seconds. Due to the complex real-world environmental ventilation conditions, a social distance longer than 1.83 m (6 feet) needs to be considered. Wearing masks should also be recommended for both infected and healthy humans to reduce the airborne cough droplet numbers.

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Section: Model Validationsmentioning

confidence: 88%

Section: Geometry and Computational Meshmentioning

confidence: 99%

Section: Governing Equationsmentioning

confidence: 99%