期刊：
Journal of Radioanalytical and Nuclear Chemistry,2021年328(1):39-47 ISSN：0236-5731
通讯作者：
Xie, Dong
作者机构：
[Wang, Chenhua; Xie, Dong] Natl & Local Joint Engn Res Ctr Airborne Pollutan, Hengyang 421001, Peoples R China.;[Wang, Chenhua; Xie, Dong; Wang, Hanqing; Yu, Chuck Wah; Yang, Xiaomin] Univ South China, Sch Civil Engn, Hengyang 421001, Peoples R China.;[Wang, Hanqing] Cent South Univ Forestry & Technol, Sch Civil Engn, Changsha 410211, Peoples R China.
通讯机构：
[Xie, Dong] N;[Xie, Dong] U;Natl & Local Joint Engn Res Ctr Airborne Pollutan, Hengyang 421001, Peoples R China.;Univ South China, Sch Civil Engn, Hengyang 421001, Peoples R China.
关键词：
Rn-222 exhalation;Temperature difference;Water content;Concrete block;Grey prediction model
摘要：
Effects of temperature difference between indoor air and concrete, and water content in concrete, on Rn-222 exhalation were investigated. In concrete with 0% water content, the heat generated due to temperature difference between concrete and indoor air could raise Rn-222 exhalation rate by 2.6 times. The Rn-222 exhalation rate rose initially, then declined as water content in concrete was increased. The maximum Rn-222 exhalation rate was 4.4 mBq m(-1) s(-1) in concrete with 10% water content. A grey prediction model was established for predicting Rn-222 exhalation rates and exposure doses of residents due to different indoor temperature differences with concrete.
期刊：
Sustainable Cities and Society,2021年66:102599 ISSN：2210-6707
通讯作者：
Xie, Dong
作者机构：
[Wang, Chenhua; Xie, Dong; Wu, Yangxi; Wang, Hanqing; Tian, Ling] Natl & Local Joint Engieering Res Ctr Airborne Po, Hengyang 421001, Peoples R China.;[Xie, Dong; Wu, Yangxi; Tian, Ling; Yu, Chuck Wah] Univ South China, Sch Civil Engn, Hengyang 421001, Peoples R China.;[Wang, Hanqing] Cent South Univ Forestry & Technol, Changsha 410004, Peoples R China.;[Yu, Chuck Wah] Int Soc Built Environm ISBE, Milton Keynes, Bucks, England.;[Xie, Dong] Univ South China, Hengyang, Hunan, Peoples R China.
通讯机构：
[Xie, Dong] U;Univ South China, Hengyang, Hunan, Peoples R China.
关键词：
Indoor radon environment;Radon diffusion and distribution;CFD simulation;Three-dimensional unsteady state;Stabilization time
摘要：
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.
摘要：
A new experimental methodology is presented to show the effect of water supply temperature, mass flow rate and thermal load distribution on the radiant ceiling capacity and thermal comfort conditions. Computerized fluid dynamics simulated vertical temperatures and velocities profiles were validated by a comparison with experimental results and the difference was within 10%. Uniform surface temperature distribution was achieved in a 45.6 m(3) test room installed with capillary ceiling radiant cooling panels by an increase in water temperature and air supply velocity. When the ventilation system was turned off, the mean ceiling surface temperature rose from 16.9 +/- 0.4 degrees C to 21.5 +/- 0.3 degrees C with a rise in the inlet water temperature to 20.1 degrees C. The temperature difference between the head and ankle of an occupant was 2.0 degrees C, which complies with the Chinese standard, GB/T 18049-2017. At a height of 1-1.5 m, the maximum temperature fluctuation was 2 degrees C in the horizontal direction. When the ventilation system was turned on, with the air supply temperature and velocity at 19.8 degrees C and 1.11 m s(-1), the ceiling surface temperature was increased by 0.5 degrees C. The indoor air temperature has a positive correlation with the air supply temperature and internal heat load but a negative correlation with air supply velocity.
摘要：
The capillary ceiling radiation cooling panel (C-CRCP) is a newly developed terminal device for air conditioning to provide indoor thermal comfort for occupants and to save energy. In this paper, numerical modelling of a room with a C-CRCP system was used to analyze radiant heat transfer under non-steady-state conditions. Experiments were conducted in an environmental chamber to verify simulation results. The chamber was equipped with a C-CRCP, which was covered with gypsumboard. The results showed that the inlet water temperature had a significant influence on ceiling surface temperature. The ceiling surface temperature and the steady-state time were increased with higher inlet water temperature. A vertical gradient in indoor air temperature was found. Ceiling surface temperature and indoor air temperature were increased with an increase in inlet air temperature. The energy supply rate of the radiant panel had a positive correlation with chilled water velocity. The amount of radiation was double the amount of convection, and the thickness of the gypsumboard had virtually no effect on the proportions of radiation and convection. The model was considered validated since the maximum relative errors between experimental data and simulation results of inlet water temperature and supply air conditions were within 10%.
作者机构：
[Xie, Dong; Wang, Yun; Mo, Shunquan; Liao, Maili] Univ South China, Sch Urban Construct, Hengyang 421001, Peoples R China.;[Xie, Dong; Wang, Hanqing] Cent S Univ, Sch Energy Sci & Engn, Changsha 410083, Hunan, Peoples R China.;[Wang, Hanqing] Hunan Univ Commerce, Changsha 410205, Hunan, Peoples R China.
通讯机构：
[Xie, Dong] U;Univ South China, Sch Urban Construct, Hengyang 421001, Peoples R China.
关键词：
CFD;Capillary ceiling radiant cooling panel;Cooling capacity;Distribution of temperature non-uniformity;Numerical analysis
摘要：
Capillary ceiling radiant cooling panel is a high temperature cooling system, which could pose low energy consumption to meet thermal comfort requirements. A computational fluid dynamics (CFD) simulation study on heat transfer of chilled water flow in the capillary of ceiling radiant cooling panel was performed to attain surface temperature distributions and cooling capacities. Six influencing factors included chilled water inlet parameters, conditions of gypsum plaster and capillary mats structural parameters were considered to obtain the complicated relationships between capillary radiant panel conditions and heat transfer performance. The index of temperature non-uniformity coefficient was proposed to evaluate temperature profiles of ceiling panel surface. The results of the simulation were compared with the values depicted in ASHRAE Handbook and good agreement had been achieved. The average difference between simulation results and the values reported by ASHRAE handbook was within the region of 15%. The research results showed that temperature non-uniformity coefficient was negatively correlated with temperature of chilled inlet water (linear correlation), water velocity (correlation coefficient R = -0.85), and pipe diameter (correlation coefficient R = -0.93), but positively and linearly correlated with tube spacing. Cooling capacity was found to have negative linear correlation with temperature of chilled inlet water, covering thickness and tube spacing. (C) 2015 Elsevier Ltd. All rights reserved.
作者机构：
[Xie, Dong; Zhou, Binkai; Wang, Yun; Mo, Shunquan] Univ South China, Sch Urban Construct, Hengyang, Hunan, Peoples R China.
会议名称：
International Conference on Energy Equipment Science and Engineering (ICEESE)
会议时间：
MAY 30-31, 2015
会议地点：
Guangzhou, PEOPLES R CHINA
会议主办单位：
[Xie, Dong;Mo, Shunquan;Wang, Yun;Zhou, Binkai] Univ South China, Sch Urban Construct, Hengyang, Hunan, Peoples R China.
摘要：
Radon (Rn-222) found in uranium mine shaft ventilation exhaust gases could pose hazards to the surrounding environment and the public by virtue of its progeny. Numerical calculations of the physical model for uranium mine under complex terrains were conducted to evaluate atmospheric dispersion and radon concentration distribution from the ventilation shaft using CFD methods. Factors of the two directions of atmospheric wind and four release height conditions (1, 3, 5 and 8 m) were considered to research radon dispersion in the study. Results showed that radon pollution in the North wind direction was more serious than in the South wind direction and radon concentration differences decreased with the increase of radon dispersion distance. The distance of radioactive contaminant transportation from shaft outlet exhaust was positively correlated with the release height within the region of 100 m. With the increasing release heights, the radon concentrations had a significant decline at a distance of 200 m.
