Experimental and numerical investigation of TVOC concentrations and ventilation dilution in enclosed train cabin

Zhao, Le; Zhou, Hongbo; Jin, Yuzhen; Li, Zeqing

doi:10.1007/s12273-021-0827-2

Cited by 15 publications

(8 citation statements)

References 36 publications

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“…The velocity ratio between the two phases was studied, and the wide operation range of countercurrent was verified. The results show that the efficiency of one-time reverse parallel extraction using this method is 4-5 times that of left and right parallel extraction [ 11 ].…”

Section: Literature Reviewmentioning

confidence: 99%

[Retracted] Application of CFD Numerical Simulation Image Imaging Technology in the Study of Droplet Microfluidic Multiphase Flow Characteristics

2022

Contrast Media & Molecular Imaging

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In order to study the problem that the flow in the internal channel of the microfluidic chip is different from that of the macroscopic system by the FD numerical simulation image imaging technology. Taking the liquid-liquid extraction of microfluidic chip as the research object, this paper analyzes the theoretical basis, working principle, structural parameters, and the influence of working parameters on the fluid flow of liquid-liquid extraction. The results are as follows: when the inlet velocity of flowing liquid is 10^(−5) m/s, the diffusion efficiency can still be maintained at 95%; the double ψ-type aqueous phase showed laminar flow, the two-phase contact interface increased compared with the bottom flow rate, and the extraction efficiency increased to 98%; the extraction efficiency of double ψ type is higher than that of double Y-type: when the flow velocity ratio increases from v a q : v oil = 1 : 2 to v a q : v oil = 5 : 1 , the extraction efficiency increases to 99.8%; the experimental extraction efficiency is compared with the diffusion efficiency simulated by simulation. The diffusion efficiency of the cross type is 1.05 times that of the extraction efficiency, and that of the cylindrical type is 1.04 times that of the extraction efficiency. In this study, CFD is used to simulate the characteristics of droplet microfluidic multiphase flow, which enriches the theoretical method and research experience of liquid-liquid laminar flow.

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Section: Literature Reviewmentioning

confidence: 99%

[Retracted] Application of CFD Numerical Simulation Image Imaging Technology in the Study of Droplet Microfluidic Multiphase Flow Characteristics

2022

Contrast Media & Molecular Imaging

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“…It was found that the PM 10 concentration in the cabin was highest in the central area where the exhaust outlets were located and gradually decreased toward both ends of the cabin. According to Zhao et al [ 13 ], indoor air quality can be improved by increasing the flow rate of the supplied air. Similar trends were also observed in the simulation results of this study.…”

Section: Resultsmentioning

confidence: 99%

“…Furthermore, changes in the concentration of TVOCs were examined while the flow velocity of the air blower in the subway train was changed in the 0.2–0.7 m/s range. It was found that the TVOC concentration in the respiratory area of passengers decreased as the flow velocity increased [ 13 ].…”

Section: Introductionmentioning

confidence: 99%

Study on the Ventilation Method to Maintain the PM10 Concentration in a Subway Cabin below 35 μg/m3

Choi

Yook

Kim

et al. 2022

Toxics

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The city of Seoul will limit the maximum particulate matter (PM10) concentration to ≤35 μg/m3 (from 2024). Herein, a numerical parametric study was conducted on the PM removal efficiency of the heating, ventilation, and air conditioning (HVAC) filters installed in the ceiling of subway cabins. The PM10 concentration distribution was explored according to the flow rate and flow rate ratio of the air introduced into the cabin. Under the current ventilation conditions of the subway train HVAC system, the PM10 concentration was highest in the cabin central area where exhaust outlets are located and decreased toward both ends of the cabin. The indoor airflow was improved and the PM10 concentration was reduced by increasing the flow rate of the supplied air at both ends of the cabin while decreasing it in the central area. It was found that the strengthened PM10 concentration criterion of Seoul can be met by increasing the ventilation flow rate to 700 CMH (currently, 500 CMH) and the filter efficiency to 85% (currently, 70%) while maintaining the current flow rate ratio. These results are expected to be used as important reference data for reducing the PM concentration in subway cabins and thereby improving indoor air quality.

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“…Before 2019, most scientific works regarding air quality were focused on the quantification of volatile organic compounds (VOCs), Benzene, Toluene, and the three Xylene isomers (BTEX) (Batterman et al 2002 ; Hsu and Huang 2009 ; Parra et al 2008 ). The study of comfort conditions was also addressed in several works on trains (Zhao et al 2022 ), airplanes (You et al 2019 ), and buses (Chan et al 2002 ). But in the last 2 years, the SARS pandemic put major interest on the airborne transmission of pathogen-laden droplets (Noorimotlagh et al 2021 ).…”

Section: Introductionmentioning

confidence: 99%

Air circulation study inside and outside of urban buses induced by the opening of windows

Corzo

Godino

Ramajo

2022

Environ Sci Pollut Res

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In this work, the external and internal airflow analysis in an urban bus is carried out through computational fluid dynamics. The research addresses the study of the internal flow to estimate the air change rate caused by the opening of windows. Two cases are considered: fully opening and partially opening the windows, and three bus speeds of 20, 40, and 60 km/h are assessed. The quantification of the air flow rate through the windows clearly displays that air enters through the rear windows and exits the bus through the front windows. This effect is explained by the pressure distribution in the outer of the bus, which causes the suction of the indoor air. At low bus speeds, the incoming air flow rate increases linearly with the speed, but the improvement is lower for high speeds. The theoretical air change time at 20 km/h is around 25.7 s, which is 9 times lower than expected by using HVAC systems. On the other hand, the estimation of the real air renewal time by solving a concentration shows that 40 s are needed to exchange 85% of the internal air of the bus. The research also assesses the effect of different levels of occupation inside the bus. Results are conclusive to recommend the circulation with full or partial window opening configurations in order to reduce the risk of airborne disease transmission.

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Experimental and numerical investigation of TVOC concentrations and ventilation dilution in enclosed train cabin

Cited by 15 publications

References 36 publications

[Retracted] Application of CFD Numerical Simulation Image Imaging Technology in the Study of Droplet Microfluidic Multiphase Flow Characteristics

[Retracted] Application of CFD Numerical Simulation Image Imaging Technology in the Study of Droplet Microfluidic Multiphase Flow Characteristics

Study on the Ventilation Method to Maintain the PM10 Concentration in a Subway Cabin below 35 μg/m3

Air circulation study inside and outside of urban buses induced by the opening of windows

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