Numerical Simulation of Influence of Vegetation on Atmospheric Diffusion of Radon Emanating from Uranium Tailings Impoundment

2012 ◽  
Vol 253-255 ◽  
pp. 1009-1013 ◽  
Author(s):  
Xiao Yong Peng ◽  
Qing Fang Xie ◽  
Fen Wan ◽  
Shuai Huang ◽  
Xin Zhang
Keyword(s):  
Numerical Simulation ◽  
Wind Speed ◽  
Radon Concentration ◽  
Simulation Method ◽  
Atmospheric Diffusion ◽  
Local Pollution ◽  
Tailings Impoundment ◽  
Radon Diffusion ◽  
The One ◽  
Uranium Tailings

Using the numerical simulation method, this thesis studies the radon concentration distribution in downwind area of the flat ground uranium tailings impoundment with and without vegetation on the beach face under the wind speed of 0.5, 1.0, 2.0 and 4.0m/s. The numerical results show that the radon concentration decreases gradually with the increasing wind speed and distance from uranium tailings impoundment. As the wind speed is 0.5m/s, the radon concentration is higher in downwind area of uranium tailings impoundment, and accumulation range is larger and local pollution also becomes more serious. However, radon concentration and accumulation range falls rapidly with wind speed increased to 4.0m/s. At the same wind speed, radon concentration under the condition of beach face with vegetation is higher than the one without vegetation within 600m range of uranium tailings impoundment along the downwind direction, but radon concentration is lower under the condition of beach face with vegetation out of 600m range. It illustrates that vegetation can inhibit radon diffusion to some extent.

Numerical Simulation of Atmospheric Migration of Particles from Uranium Tailings Impoundment

2012 ◽  
Vol 253-255 ◽  
pp. 1014-1018
Author(s):  
Xiao Yong Peng ◽  
Fen Wan ◽  
Qing Fang Xie ◽  
Xin Zhang ◽  
Shuai Huang
Keyword(s):  
Numerical Simulation ◽  
Wind Speed ◽  
Particle Concentration ◽  
Dust Emission ◽  
Local Concentration ◽  
Discrete Phase Model ◽  
Local Pollution ◽  
Tailings Impoundment ◽  
And Migration ◽  
Uranium Tailings

Based on the discrete phase model (DPM), this paper studies the concentration distribution and settlement regularity of particles which sizes are 10μm and 100μm under the wind speed of 0.5, 1, 2, and 4m/s with the method of numerical simulation. The simulation results show that the particle concentration of 10μm at the downwind direction of tailing is constantly decreasing with the increase of wind speed and migration distance, and the particle concentration of 100μm is gradually increasing, as well as the local pollution also become gradually worse. As wind speed is 0.5m/s, the local concentration of 10μm particles at the beach face of uranium tailings impoundment is higher, and there is much deposition within 2000m of the downwind direction. While the dust emission rate of 100μm is less and its concentration is lower.10μm particles are taken away by the wind, and its concentration would fall rapidly with wind speed increased to 4.0m/s. The concentration of 100μm particle would increase and local pollution becomes more serious.

Numerical Simulation of Atmospheric Diffusion of Radon Emanating From Flat Ground Uranium Tailings Impoundment in Different Heights

2012 ◽  
Vol 518-523 ◽  
pp. 1677-1681 ◽  
Author(s):  
Xiao Yong Peng ◽  
Zhen Hao Liu ◽  
Qing Fang Xie ◽  
Xin Zhang ◽  
Fen Wan ◽  
...  
Keyword(s):  
Radon Concentration ◽  
Concentration Distribution ◽  
National Standard ◽  
Radon Emanation ◽  
Atmospheric Diffusion ◽  
Tailings Impoundment ◽  
Effective Doses ◽  
The Difference ◽  
Uranium Tailings ◽  
Flat Ground

The atmospheric diffusion and concentration distribution of radon (emanation rate is 6.06 Bq/m2s ) emanating from the flat ground uranium tailings impoundment at various heights(0m, 10m, 20m, and 30m) are simulated. The numerical results show that the different height of the tailings impoundment will mainly influence the radon concentration that could change in the range of 16~250 Bq/m3 at the downwind region of 0-300m. The radon concentration and annual effective doses for public from radon decrease sharply with the increasing distance away from tailings impoundment, are higher than that of the decommissioned uranium tailings impoundment (its height is 30m, radon emanation rate is 0.74 Bq/m2s ). The annual effective doses for public from radon are highly up to 1.12 mSv/a, and are 0.12 mSv/a greater than the national standard in the range of 800m. Considering the difference of average radon emanation rate and other factors, the protective distance from radon should be adjusted appropriately.

Numerical Simulation of Radon Atmospheric Dynamic Diffusion from a Flat Ground Uranium Tailings Impoundment

2013 ◽  
Vol 807-809 ◽  
pp. 628-631
Author(s):  
Xiao Yong Peng ◽  
Xin Zhang ◽  
Shuai Huang ◽  
Xu Sheng Chai ◽  
Lan Xia Guo
Keyword(s):  
Numerical Simulation ◽  
Mass Fraction ◽  
Space Distribution ◽  
Time And Space ◽  
Tailings Impoundment ◽  
Diffusion Characteristics ◽  
Atmospheric Dynamic ◽  
Uranium Tailings ◽  
Dynamic Diffusion ◽  
Flat Ground

with a flat ground uranium tailings impoundment as the object of the paper, CFD technology was used to study the atmospheric dynamic diffusion characteristics and the evolution of time and space distribution of radon in the uranium tailings impoundment. Results show that, within 1500m range of the leeward of uranium tailings impoundment the falling gradient of radon mass fraction improves with distance increases at the same moment, however the falling gradient flattens with the increase of time gradually; During the first 30 minutes, the radon mass fraction of tailings impoundment in the leeward direction has a larger growth gradient, then flattens out slowly, and stabilizes after 75 minutes.

Diffusion Law and Simulation Analysis of Radon in Uranium Tailings Based on Multiple Gauss Plume Model

2018 ◽  
Author(s):  
Jiaxin Wang ◽  
Guohua Wu ◽  
Liguo Zhang ◽  
Jingyuan Qu ◽  
Jiejuan Tong
Keyword(s):  
Wind Speed ◽  
Radon Concentration ◽  
Single Point ◽  
Atmospheric Stability ◽  
Radiation Hazard ◽  
Downwind Distance ◽  
Average Wind Speed ◽  
Near Surface ◽  
Wide Range ◽  
Uranium Tailings

The radon from uranium tailings spreads fast and has a wide range of pollution, which poses a potential radiation hazard to the environment and the public in downwind region. In this paper, the open and naked uranium tailings are selected as research object. By setting up multiple Gaussian plume models with single point source, the diffusion of radon in the uranium tailings is simulated with different atmospheric stability, average wind speed, height and downwind distance. The results show that the maximum radon concentration increases while the related downwind distance decreases as the atmospheric becoming stable. The higher wind speed does not affect the downwind distance where the maximum radon concentration occurs, but it decreases the maximum radon concentration. The concentration of radon in residential area decreases but the decreasing rate speeds up with height going up. The distribution of radon in vertical and horizontal direction tends to be homogeneous while the near-surface area concentration decreases rapidly as farther downwind distance.

Numerical Simulation of the Vegetation Effect on Tailing Sand Atmospheric Transport in Uranium Tailing Impoundment

2013 ◽  
Vol 726-731 ◽  
pp. 1613-1618
Author(s):  
Xiao Yong Peng ◽  
Xin Zhang ◽  
Shuai Huang ◽  
Xu Sheng Chai ◽  
Lan Xia Guo ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Vegetation Cover ◽  
Particle Concentration ◽  
Atmospheric Transport ◽  
Simulation Method ◽  
Horizontal Distance ◽  
Migration Distance ◽  
And Migration ◽  
Uranium Tailings ◽  
Vegetation Effect

For two conditions of (non-) vegetation cover in uranium tailings beach face, the concentration distribution and settlement regularity of tailing sand with diameter of 10μm at speed of 0.5, 1, 2, and 4 m/s was studied by numerical simulation method. Results shows, with the increase of wind speed and migration distance, particle concentration decreases. Compared with the non-vegetation cover condition, particles concentration in the condition of with vegetation cover is significantly higher than the condition that without vegetation cover; but along with the increase of horizontal distance, the concentration lowers than the latter gradually.

The Simulation and Experiment Study on the Gas Flow in the No-Loaded and Cold Vacuum High-Pressure Gas Quenching Furnace

2011 ◽  
Vol 48-49 ◽  
pp. 1310-1314
Author(s):  
Zhi Jian Wang ◽  
Xiao Feng Shang
Keyword(s):  
Numerical Simulation ◽  
High Pressure ◽  
Gas Flow ◽  
Flow Distribution ◽  
Simulation Method ◽  
Flow State ◽  
Gas Quenching ◽  
Simulation And Experiment ◽  
Simulation Results ◽  
The One

In order to learn gas flow state in the vacuum high pressure gas quenching furnace, this paper simulates and tests the gas flow under the no-loaded and cold state. Hot wire anemometer is used to measure the speeds of some feature points, on the one hand to provide boundary conditions for the numerical simulation, and on the other hand to compare with the numerical simulation results. FLUENT software is used to simulate the gas flow of nozzle-type vacuum high-pressure gas quenching furnace. The results show that at the center of the furnace appears high-pressure low-speed zone in which is resulted by the gas collision there, and the vortex also appears in the area around the furnace. The results mean that the cooling rate of works will be slow there. Different exit velocities of five nozzles cause the uneven flow distribution, which will affect the cooling uniformity of works. The comparison between the simulation results and the measured results shows that the error is within 10%. It means that numerical simulation method to predict gas flow is feasible and the results are reliable in high pressure gas quenching furnace.

Field Investigation and Wind-Environment Numerical Simulation of Cable-Stayed Bridge Site in the West Midlands Region

2011 ◽  
Vol 255-260 ◽  
pp. 4202-4206
Author(s):  
Yue Zhang ◽  
Mi Zhou
Keyword(s):  
Numerical Simulation ◽  
Wind Speed ◽  
Field Investigation ◽  
Wind Flow ◽  
Observation Data ◽  
Bridge Site ◽  
Wind Speed Profile ◽  
Long Span Bridges ◽  
Long Span ◽  
The One

The area of mountain ridge accounts for the most part of our country land. With the development of economic construction, more and more long span bridges have been built in the mountainous region of the western in China.. Combining live observed wind with numeric simulation, the wind characteristics on the western gap of valley areas are studied. On the one hand through the self-development processing of the bridge speed data to analyze massive wind observation data, the parameters (such as wind speed profile, turbulence intensity, power spectral density) used as the main basis for calculating wind loads are achieved. On the other hand wind flow around the bridge site as well as the environment around the mountain wind flow, wind speed field and the distribution of turbulent flow, etc is obtained by using CFD technology. Based on the results that is compared with that of numerical simulation by FLUENT, the reliability and efficiency of the program is testified. It would be provided with great theoretical significance and practical engineering value passes through the foregoing study.

Wind Speed Profiles of an Actual Downburst Based on CFD Numerical Simulation

2012 ◽  
Vol 170-173 ◽  
pp. 3411-3414
Author(s):  
Yan Li ◽  
Wei Lian Qu ◽  
Bai Feng Ji ◽  
Yi Fei Wang
Keyword(s):  
Numerical Simulation ◽  
Wind Speed ◽  
Initial Conditions ◽  
Cloud Model ◽  
Simulation Method ◽  
Wind Load ◽  
Strong Wind ◽  
Speed Profile ◽  
Transmission Tower ◽  
Wind Speed Profile

Downbursts have led to large number of transmission tower failures in the world, so more and more wind engineers are very interested in such strong wind load. Currently the main numerical simulation method of downburst wind load for structural analysis is based on the horizontal divergent wind speed profile of downburst. There have been several available types of empirical wind speed profiles in which some parameters still need to be artificially determined. So, this is a semi-empirical-analytical method which can not be linked with actual downbursts. Some academics have also used CFD numerical method to simulate downburst wind speed profile of high precision grid. But the initial conditions of these CFD simulations were all assumed ideally. In this paper, the wind speed profiles of an actual downburst are simulated by CFD method based on the initial speed of downdraft entrance provided by cloud model. The simulated wind speed profile decays more slowly than an empirical wind speed profile. This conclusion could be of significance for structural engineers to consider downburst wind load reasonably in the structural wind resistant design.

Study of Precision Formation on New Synchronizing Ring of Heavy-Duty Truck Based on Computer Numerical Simulation

2011 ◽  
Vol 189-193 ◽  
pp. 2317-2321
Author(s):  
Jie Chen ◽  
Xiu Mei Yang
Keyword(s):  
Numerical Simulation ◽  
New Product Development ◽  
Simulation Method ◽  
Friction Torque ◽  
Forming Process ◽  
One Step ◽  
Material Forming ◽  
Computer Numerical Simulation ◽  
The One ◽  
Processing Optimization

Synchronizing ring, an important component of automotive synchronizer, uses the friction torque generated on its conical surface to synchro-mesh the two meshing components to realize gear shift. In the paper the forming of the hot precision forging of the new synchronizing ring is analyzed based on the finite element numerical simulation method, which provides evidence for processing optimization and mould modifying to get an accurate blank. In addition, the one-step forming processing for the synchronizing ring is analyzed, and the flow of the material, forming process, flaw prediction and the optimization of the mould structure is studied as well. The result indicates that it is more reasonable of the distribution of the material and it is more satiation filled of the cavities. The cycle life of new product development is reduced greatly by forming process analyzing and flaw prediction of the synchronizing ring.

Optimum Design of CFG Pile Compound Foundation Based on Numerical Simulation Method

2014 ◽  
Vol 578-579 ◽  
pp. 346-350 ◽  
Author(s):  
Hai Ying Cao ◽  
Yun Fei Liu
Keyword(s):  
Numerical Simulation ◽  
Computational Models ◽  
Simulation Method ◽  
Simulation Software ◽  
Design Parameters ◽  
Conventional Design ◽  
Bearing Force ◽  
The One ◽  
Pile Length ◽  
Cfg Pile

Aiming at the phenomenon of empirical selection in CFG pile compound foundation's design parameters, the computational models considering different pile length were built by numerical simulation software PLAXIS, whose background came from an actual highway engineering. The relation curves were plotted and analyzed concerning pile length with subgrade horizontal deformation, subgrade settlement, integral stability of embankment and end bearing force of pile, in the light of deformation and stress cloud graphs from post-processing results. The feasibility of pile length optimization in conventional design was judged synthetically according to above mentioned curves, and the optimized pile length was 2m shorter than the one of conventional design, which cut down construction cost. The construction practice indicates that there are not abnormal occurrence in subgrade treatment section during period of traffic operation.

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