The Experts below are selected from a list of 159 Experts worldwide ranked by ideXlab platform
Hanqing Wang - One of the best experts on this subject based on the ideXlab platform.
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A study on the three-dimensional unsteady state of indoor radon diffusion under different ventilation conditions
Sustainable Cities and Society, 2021Co-Authors: Dong Xie, Chenhua Wang, Ling Tian, Hanqing WangAbstract:Abstract The exhalation of radon from building materials is a serious risk to occupants’ health. This paper studied the indoor radon diffusion under three-dimensional unsteady conditions. The radon exhalation rate of building materials was measured using a radon collection chamber combined with a RAD7-based radon/thoron detector. The indoor radon diffusion under different ventilation patterns were simulated by CFD (Computational fluid dynamics) based on the stabilization of radon concentration after 10 h in a closed environment as an initial condition. The results show that the stabilization time is 20 min, which can be reduced by appropriately increasing the air Inlet velocity. Further increase in air velocity from 0.3 m s−1 did not produce any significant changes in the stabilization time and the average radon concentration. Our findings show that the better way to reduce indoor radon concentration is to have the air Supply Inlet at the top or upper side and the air return outlet on the lower side of the room. The indoor radon can be reduced to a steady level after 20 min using the better ventilation method. The findings would contribute to the control of the indoor radon dispersion, and to alleviate and reduce occupants’ exposure to high radioactive concentration of radon in urban cities.
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A study on the three-dimensional unsteady state of indoor radon diffusion under different ventilation conditions
Sustainable Cities and Society, 1Co-Authors: Dong Xie, Chenhua Wang, Ling Tian, Hanqing WangAbstract:Abstract The exhalation of radon from building materials is a serious risk to occupants’ health. This paper studied the indoor radon diffusion under three-dimensional unsteady conditions. The radon exhalation rate of building materials was measured using a radon collection chamber combined with a RAD7-based radon/thoron detector. The indoor radon diffusion under different ventilation patterns were simulated by CFD (Computational fluid dynamics) based on the stabilization of radon concentration after 10 hours in a closed environment as an initial condition. The results show that the stabilization time is 20 minutes, which can be reduced by appropriately increasing the air Inlet velocity. Further increase in air velocity from 0.3 m s-1 did not produce any significant changes in the stabilization time and the average radon concentration. Our findings show that the better way to reduce indoor radon concentration is to have the air Supply Inlet at the top or upper side and the air return outlet on the lower side of the room. The indoor radon can be reduced to a steady level after 20 minutes using the better ventilation method. The findings would contribute to the control of the indoor radon dispersion, and to alleviate and reduce occupants’ exposure to high radioactive concentration of radon in urban cities.
Dong Xie - One of the best experts on this subject based on the ideXlab platform.
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A study on the three-dimensional unsteady state of indoor radon diffusion under different ventilation conditions
Sustainable Cities and Society, 2021Co-Authors: Dong Xie, Chenhua Wang, Ling Tian, Hanqing WangAbstract:Abstract The exhalation of radon from building materials is a serious risk to occupants’ health. This paper studied the indoor radon diffusion under three-dimensional unsteady conditions. The radon exhalation rate of building materials was measured using a radon collection chamber combined with a RAD7-based radon/thoron detector. The indoor radon diffusion under different ventilation patterns were simulated by CFD (Computational fluid dynamics) based on the stabilization of radon concentration after 10 h in a closed environment as an initial condition. The results show that the stabilization time is 20 min, which can be reduced by appropriately increasing the air Inlet velocity. Further increase in air velocity from 0.3 m s−1 did not produce any significant changes in the stabilization time and the average radon concentration. Our findings show that the better way to reduce indoor radon concentration is to have the air Supply Inlet at the top or upper side and the air return outlet on the lower side of the room. The indoor radon can be reduced to a steady level after 20 min using the better ventilation method. The findings would contribute to the control of the indoor radon dispersion, and to alleviate and reduce occupants’ exposure to high radioactive concentration of radon in urban cities.
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A study on the three-dimensional unsteady state of indoor radon diffusion under different ventilation conditions
Sustainable Cities and Society, 1Co-Authors: Dong Xie, Chenhua Wang, Ling Tian, Hanqing WangAbstract:Abstract The exhalation of radon from building materials is a serious risk to occupants’ health. This paper studied the indoor radon diffusion under three-dimensional unsteady conditions. The radon exhalation rate of building materials was measured using a radon collection chamber combined with a RAD7-based radon/thoron detector. The indoor radon diffusion under different ventilation patterns were simulated by CFD (Computational fluid dynamics) based on the stabilization of radon concentration after 10 hours in a closed environment as an initial condition. The results show that the stabilization time is 20 minutes, which can be reduced by appropriately increasing the air Inlet velocity. Further increase in air velocity from 0.3 m s-1 did not produce any significant changes in the stabilization time and the average radon concentration. Our findings show that the better way to reduce indoor radon concentration is to have the air Supply Inlet at the top or upper side and the air return outlet on the lower side of the room. The indoor radon can be reduced to a steady level after 20 minutes using the better ventilation method. The findings would contribute to the control of the indoor radon dispersion, and to alleviate and reduce occupants’ exposure to high radioactive concentration of radon in urban cities.
Kyeong-seok Kwon - One of the best experts on this subject based on the ideXlab platform.
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Tracer gas experiment for local mean ages of air from individual Supply Inlets in a space with multiple Inlets
Building and Environment, 2011Co-Authors: Hwataik Han, Cheol-yong Shin, In-bok Lee, Kyeong-seok KwonAbstract:We investigate the Supply characteristics of incoming air via individual Inlets in a ventilated space with multiple Inlets. Theoretical considerations are given to determine the relations between the local mean age (LMA) of the total Supply air and the individual LMA of each Supply air Inlet. Tracer gas experiments are conducted in a simplified livestock model with two Supply Inlets and one exhaust outlet. Transient concentration responses at internal points are measured after tracer gas injection one Inlet at a time, and for simultaneous tracer injection at both Inlets. The spatial distributions of LMAs and steady concentrations are obtained by tracer injections from each Supply Inlet, which demonstrate the Supply characteristics of the individual Inlets in the space. We have found that the overall LMA is the weighted average of the LMA by each Inlet, and the weighting factor for the average is the corresponding steady state concentration at a given point. Experiments repeated for various airflow rates show that the nondimensional steady concentrations remain nearly constant regardless of the total airflow rate, but are greatly influenced by the airflow ratio between Inlets. The local mean ages are found to increase proportionally with respect to the nominal time constant. Experimental procedures and results are verified by the fact that the total LMA measured at the exhaust is in good agreement with the theoretical nominal time constant of the space.
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LOCAL MEAN AGES OF AIR IN A ROOM WITH MULTIPLE InletS
International Journal of Air-Conditioning and Refrigeration, 2010Co-Authors: Hwataik Han, Cheol-yong Shin, In-bok Lee, Kyeong-seok KwonAbstract:This paper considers the age of air in a ventilated space with multiple Supply Inlets; the local mean age (LMA) of air is different from one Inlet to another in multiple Supply Inlet situations. The purpose of this paper is to investigate theoretically the relations between the LMAs arising from each Supply Inlet and the overall combined LMA for all Inlets. Transient concentration distributions are calculated using a CFD package in a simple room configuration with two Inlets and one outlet, to verify the relations. Tracer gases are injected with a step-up method at each Supply Inlet individually, and at both Inlets simultaneously. As a result, it can be found that the steady state concentration, with a continuous tracer injection at each Supply Inlet, works as a weighting factor for the corresponding LMA in calculating the overall combined LMA for the multiple Inlet situations.
Ling Tian - One of the best experts on this subject based on the ideXlab platform.
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A study on the three-dimensional unsteady state of indoor radon diffusion under different ventilation conditions
Sustainable Cities and Society, 2021Co-Authors: Dong Xie, Chenhua Wang, Ling Tian, Hanqing WangAbstract:Abstract The exhalation of radon from building materials is a serious risk to occupants’ health. This paper studied the indoor radon diffusion under three-dimensional unsteady conditions. The radon exhalation rate of building materials was measured using a radon collection chamber combined with a RAD7-based radon/thoron detector. The indoor radon diffusion under different ventilation patterns were simulated by CFD (Computational fluid dynamics) based on the stabilization of radon concentration after 10 h in a closed environment as an initial condition. The results show that the stabilization time is 20 min, which can be reduced by appropriately increasing the air Inlet velocity. Further increase in air velocity from 0.3 m s−1 did not produce any significant changes in the stabilization time and the average radon concentration. Our findings show that the better way to reduce indoor radon concentration is to have the air Supply Inlet at the top or upper side and the air return outlet on the lower side of the room. The indoor radon can be reduced to a steady level after 20 min using the better ventilation method. The findings would contribute to the control of the indoor radon dispersion, and to alleviate and reduce occupants’ exposure to high radioactive concentration of radon in urban cities.
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A study on the three-dimensional unsteady state of indoor radon diffusion under different ventilation conditions
Sustainable Cities and Society, 1Co-Authors: Dong Xie, Chenhua Wang, Ling Tian, Hanqing WangAbstract:Abstract The exhalation of radon from building materials is a serious risk to occupants’ health. This paper studied the indoor radon diffusion under three-dimensional unsteady conditions. The radon exhalation rate of building materials was measured using a radon collection chamber combined with a RAD7-based radon/thoron detector. The indoor radon diffusion under different ventilation patterns were simulated by CFD (Computational fluid dynamics) based on the stabilization of radon concentration after 10 hours in a closed environment as an initial condition. The results show that the stabilization time is 20 minutes, which can be reduced by appropriately increasing the air Inlet velocity. Further increase in air velocity from 0.3 m s-1 did not produce any significant changes in the stabilization time and the average radon concentration. Our findings show that the better way to reduce indoor radon concentration is to have the air Supply Inlet at the top or upper side and the air return outlet on the lower side of the room. The indoor radon can be reduced to a steady level after 20 minutes using the better ventilation method. The findings would contribute to the control of the indoor radon dispersion, and to alleviate and reduce occupants’ exposure to high radioactive concentration of radon in urban cities.
Chenhua Wang - One of the best experts on this subject based on the ideXlab platform.
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A study on the three-dimensional unsteady state of indoor radon diffusion under different ventilation conditions
Sustainable Cities and Society, 2021Co-Authors: Dong Xie, Chenhua Wang, Ling Tian, Hanqing WangAbstract:Abstract The exhalation of radon from building materials is a serious risk to occupants’ health. This paper studied the indoor radon diffusion under three-dimensional unsteady conditions. The radon exhalation rate of building materials was measured using a radon collection chamber combined with a RAD7-based radon/thoron detector. The indoor radon diffusion under different ventilation patterns were simulated by CFD (Computational fluid dynamics) based on the stabilization of radon concentration after 10 h in a closed environment as an initial condition. The results show that the stabilization time is 20 min, which can be reduced by appropriately increasing the air Inlet velocity. Further increase in air velocity from 0.3 m s−1 did not produce any significant changes in the stabilization time and the average radon concentration. Our findings show that the better way to reduce indoor radon concentration is to have the air Supply Inlet at the top or upper side and the air return outlet on the lower side of the room. The indoor radon can be reduced to a steady level after 20 min using the better ventilation method. The findings would contribute to the control of the indoor radon dispersion, and to alleviate and reduce occupants’ exposure to high radioactive concentration of radon in urban cities.
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A study on the three-dimensional unsteady state of indoor radon diffusion under different ventilation conditions
Sustainable Cities and Society, 1Co-Authors: Dong Xie, Chenhua Wang, Ling Tian, Hanqing WangAbstract:Abstract The exhalation of radon from building materials is a serious risk to occupants’ health. This paper studied the indoor radon diffusion under three-dimensional unsteady conditions. The radon exhalation rate of building materials was measured using a radon collection chamber combined with a RAD7-based radon/thoron detector. The indoor radon diffusion under different ventilation patterns were simulated by CFD (Computational fluid dynamics) based on the stabilization of radon concentration after 10 hours in a closed environment as an initial condition. The results show that the stabilization time is 20 minutes, which can be reduced by appropriately increasing the air Inlet velocity. Further increase in air velocity from 0.3 m s-1 did not produce any significant changes in the stabilization time and the average radon concentration. Our findings show that the better way to reduce indoor radon concentration is to have the air Supply Inlet at the top or upper side and the air return outlet on the lower side of the room. The indoor radon can be reduced to a steady level after 20 minutes using the better ventilation method. The findings would contribute to the control of the indoor radon dispersion, and to alleviate and reduce occupants’ exposure to high radioactive concentration of radon in urban cities.
