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 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 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.

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.

Numerical Simulation on U(VI) in Uranium Tailing Impoundment Affected by Acid Rain

2014 ◽  
Vol 986-987 ◽  
pp. 713-718
Author(s):  
Shuang Long Ouyang ◽  
Shu Zhan Li ◽  
Shu Kui Zhou ◽  
Hua Li ◽  
Hai Hao Jiang ◽  
...  
Keyword(s):  
Acid Rain ◽  
Maximum Speed ◽  
Radionuclide Migration ◽  
Effect Assessment ◽  
Groundwater Movement ◽  
Partitioning Coefficient ◽  
Tailings Impoundment ◽  
Maximum Value ◽  
And Migration ◽  
Uranium Tailings

As acid rain getting more and more serious, increasing attention is given to environmental effect assessment of uranium tailings under the condition of acid rain. In the paper, influence of acid rain to partitioning coefficient (Kd) of U(VI) in soil was studied, and migration of radionuclide uranium in soil was simulated by computer. The static experiment results showed that the Kd value of U(VI) in soil reaches minimum value when pH is 2.0. When 2.0<pH<3.5, the Kd showed a rising tendency;The Kd in soil reaches maximum value when pH is 3.5. And when 3.5<pH<8.0, the Kd showed a decreasing tendency. This paper has taken a large uranium tailings impoundment in South China as an example studied by VisualModflow. After setting up models of groundwater movement and radionuclide migration in the study area, migration tendency of radionuclide U(VI) was simulated and pollution of radionuclide to environment was predicted. The results of simulation show that the migration of uranium speed to be the slowest when pH = 2.0, and the figure to be the fastest when pH = 3.5. Furthermore, maximum speed is about 1.24 times of minimum speed.

Numerical Simulation on the Temperature Characteristics of Indirect Air Cooling System

2015 ◽  
Vol 741 ◽  
pp. 536-540
Author(s):  
Xiao Zhi Qiu ◽  
Yan Ming Zhao ◽  
Bao Hua Huang ◽  
Wei Xu
Keyword(s):  
Numerical Simulation ◽  
Wind Speed ◽  
Cooling System ◽  
System Change ◽  
Temperature Characteristic ◽  
Air Cooling ◽  
Ansys Software ◽  
System A ◽  
Air Cooling System ◽  
Simulation Results

Based on the analysis of indirect air cooling system, a numerical simulation model of indirect air cooling system was constructed by ANSYS software. According to the different wind speed condition, the temperature characteristic of indirect air cooling system was analyzed. The simulation results show that with the increase of wind speed, the ventilation and heat release of the indirect air cooling system change greatly. It provides a theoretical basis for the design of the wind-proof device of indirect air cooling system.

Dependence of Aerosol Particle Concentration in Surface Air over the Moscow Region on Wind Speed and Lapse Rate

2021 ◽  
pp. 103-110
Author(s):  
E. A. Stulov ◽  
◽  
E. V. Sosnikova ◽  
N. A. Monakhova ◽  
◽  
...  
Keyword(s):  
Surface Layer ◽  
Wind Speed ◽  
Particle Concentration ◽  
Meteorological Factors ◽  
Lapse Rate ◽  
Radiosonde Data ◽  
Vertical Temperature Gradient ◽  
Vertical Temperature ◽  
Simple Estimation ◽  
The City

Based on the daily measurements of atmospheric aerosol characteristics in the city of Dolgoprudny (20 km from the center of Moscow) carried out during 2013-2018, the influence of some meteorological factors on the concentration of various aerosol fractions in the surface layer of the atmosphere is analyzed. It is that the aerosol concentration depends most on the wind speed and the vertical temperature gradient. The method of simple estimation of aerosol particles accumulation conditions in the surface layer based on the use of standard radiosonde data is developed.

scholarly journals Influence of frontal cyclone evolution on the 2009 (Ekman) and 2010 (Franklin) Loop Current eddy detachment events

Ocean Science ◽  
2014 ◽  
Vol 10 (6) ◽  
pp. 947-965 ◽  
Author(s):  
Y. S. Androulidakis ◽  
V. H. Kourafalou ◽  
M. Le Hénaff
Keyword(s):  
Numerical Simulation ◽  
Gulf Of Mexico ◽  
Satellite Data ◽  
Potential Vorticity ◽  
In Situ Measurements ◽  
Loop Current ◽  
Positive Potential ◽  
Eastern Gulf Of Mexico ◽  
And Migration

Abstract. The anticyclonic Loop Current Eddy (LCE) shedding events are strongly associated with the evolution of Loop Current Frontal Eddies (LCFEs) over the eastern Gulf of Mexico (GoM). A numerical simulation, in tandem with in situ measurements and satellite data, was used to investigate the Loop Current (LC) evolution and the surrounding LCFE formation, structure, growth and migration during the Eddy Ekman and Eddy Franklin shedding events in the summers of 2009 and 2010, respectively. During both events, northern GoM LCFEs appeared vertically coherent to at least 1500 m in temperature observations. They propagated towards the base of the LC, where, together with the migration of Campeche Bank (southwest GoM shelf) eddies from south of the LC, contributed to its "necking-down". Growth of Campeche Bank LCFEs involved in Eddy Franklin was partially attributed to Campeche Bank waters following upwelling events. Slope processes associated with such upwelling included offshore exports of high positive potential vorticity that may trigger cyclone formation and growth. The advection and growth of LCFEs, originating from the northern and southern GoM, and their interaction with the LC over the LCE detachment area favor shedding conditions and may contribute to the final separation of the LCE.

scholarly journals Study on the Efficiency and Dynamic Characteristics of an Energy Harvester Based on Flexible Structure Galloping

Energies ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 6548
Author(s):  
Peng Liao ◽  
Jiyang Fu ◽  
Wenyong Ma ◽  
Yuan Cai ◽  
Yuncheng He
Keyword(s):  
Numerical Simulation ◽  
Wind Speed ◽  
Physical Model ◽  
Energy Harvester ◽  
High Efficiency ◽  
Lateral Displacement ◽  
Maximum Output Power ◽  
Flexible Structure ◽  
Maximum Output ◽  
Cfd Numerical Simulation

According to the engineering phenomenon of the galloping of ice-coated transmission lines at certain wind speeds, this paper proposes a novel type of energy harvester based on the galloping of a flexible structure. It uses the tension generated by the galloping structure to cause periodic strain on the piezoelectric cantilever beam, which is highly efficient for converting wind energy into electricity. On this basis, a physical model of fluid–structure interaction is established, and the Reynolds-averaged Navier–Stokes equation and SST K -ω turbulent model based on ANSYS Fluent are used to carry out a two-dimensional steady computational fluid dynamics (CFD) numerical simulation. First, the CFD technology under different grid densities and time steps is verified. CFD numerical simulation technology is used to simulate the physical model of the energy harvester, and the effect of wind speed on the lateral displacement and aerodynamic force of the flexible structure is analyzed. In addition, this paper also carries out a parameterized study on the influence of the harvester’s behavior, through the wind tunnel test, focusing on the voltage and electric power output efficiency. The harvester has a maximum output power of 119.7 μW/mm3 at the optimal resistance value of 200 KΩ at a wind speed of 10 m/s. The research results provide certain guidance for the design of a high-efficiency harvester with a square aerodynamic shape and a flexible bluff body.

scholarly journals Influence of the Visitor Walking on Airflow and the Bioaerosol Particles in Typical Open Tomb Chambers: An Experimental and Case Study

Buildings ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 538
Author(s):  
Zhijian Liu ◽  
Minnan Wu ◽  
Hongwei Cao ◽  
Yongxin Wang ◽  
Rui Rong ◽  
...  
Keyword(s):  
Potential Risk ◽  
Deposition Time ◽  
Scientific Basis ◽  
Discrete Phase Model ◽  
Migration Mechanism ◽  
Discrete Phase ◽  
And Migration ◽  
The Impact ◽  
Experimental Sampling

Effective maintenance of ancient buildings is paid more and more attention worldwide. Many ancient buildings with high inheritance value were gradually destroyed, especially for murals in the open tombs. The bioaerosol particles (BPs) are the major source of contamination in murals and visitor walking could increase this hazard. In order to study the impact of visitors walking on the air flow and the distribution of BPs in the typical tomb chambers, the k-ε and Lagrangian discrete phase model were adopted. The walking visitor was described by the dynamic mesh, and the concentration of BPs in the simulation was verified by experimental sampling. The distribution and migration mechanism of contamination in the chamber were dynamically analyzed. The results indicate that the denser vortex generated when a visitor was walking, and the concentration of BPs changed obviously. Therefore, the number of BPs deposited on some precious murals increased and the contamination location shifted in the direction of visitor walking. In addition, the deposition time of BPs was lagging which would cause potential risk. This research can provide scientific basis for reducing murals contamination during visitor visiting and a reference for the maintenance of ancient buildings.

scholarly journals Numerical Simulation and Wind Tunnel Investigation on Static Characteristics of VAWT Rotor Starter with Lift-Drag Combined Structure

Energies ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 6167
Author(s):  
Fang Feng ◽  
Guoqiang Tong ◽  
Yunfei Ma ◽  
Yan Li
Keyword(s):  
Numerical Simulation ◽  
Wind Speed ◽  
Wind Tunnel ◽  
Wind Turbine ◽  
Wind Turbines ◽  
Speed Ratio ◽  
Static Characteristics ◽  
Torque Coefficient ◽  
Starting Characteristics ◽  
Static Torque

In order to get rid of the impact of the global financial crisis and actively respond to global climate change, it has become a common choice for global economic development to develop clean energy such as wind energy, improve energy efficiency and reduce greenhouse gas emissions. With the advantages of simple structure, unnecessary facing the wind direction, and unique appearance, the vertical axis wind turbine (VAWT) attracts extensive attention in the field of small and medium wind turbines. The lift-type VAWT exhibits outstanding aerodynamic characteristics at a high tip speed ratio, while the starting characteristics are generally undesirable at a low wind speed; thus, how to improve the starting characteristics of the lift-type VAWT has always been an important issue. In this paper, a lift-drag combined starter (LDCS) suitable for lift-type VAWT was proposed to optimize the starting characteristics of lift-type VAWT. With semi-elliptical drag blades and lift blades equipped on the middle and rear part outside the starter, the structure is characterized by lift-drag combination, weakening the adverse effect of the starter with semi-elliptical drag blades alone on the output performance of the original lift-type VAWT and improving the characteristics of the lift-drag combined VAWT. The static characteristic is one of the important starting characteristics of the wind turbine. The rapid development of computational fluid dynamics has laid a solid material foundation for VAWT. Thus the static characteristics of the LDCS with different numbers of blades were investigated by conducting numerical simulation and wind tunnel tests. The results demonstrated that the static torque coefficient of LDCS increased significantly with the increased incoming wind speed. The average value of the static torque coefficient also increased significantly. This study can provide guidelines for the research of lift-drag combined wind turbines.

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