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Innovation point
(1) Based on the preliminary study of the characteristics of the transonic flow field in the compressible gas tube, combined with the theory of supersonic transverse jet atomization, the supersonic siphon siphon aerosolization technology is proposed, and the corresponding atomization device is developed.
(2) In this paper, experimental and numerical simulation methods were used to study the atomization and spray dust reduction characteristics of different open taper supersonic water siphon pneumatic atomization devices under different aerodynamic pressures, and the spray dust reduction mechanism was revealed.
(3) According to the atomization and spray dust reduction characteristics of supersonic water siphon siphon atomization device, a full-section supersonic water siphon curtain dust reduction system is constructed in the underground return wind lane of coal mine, and the dust reduction effect is good after application.
Supersonic water siphon pneumatic atomization dust reduction technology
Authors: Zhang Tian1,2, Jing Deji1,2, Ge Shaocheng3, Wang Jiren1,2, Ren Shuai1,2, Meng Xiangxi1,2
Units: 1. School of Safety Science and Engineering, Liaoning Technical University, 2. Key Laboratory of Mine Thermodynamic Disaster and Prevention of Ministry of Education; 3. School of Safety and Emergency Management Engineering, Taiyuan University of Technology
Background
Dust pollution is one of the important disasters in the coal mining industry, and respiratory dust with an aerodynamic particle size of less than 7.07 μm can enter the human body through respiration, seriously endangering the health of mine staff. At present, the micron-level spray dust reduction method is the most effective and inexpensive way to control such dust, but because the closer the size of the fog droplets to the dust, the greater the probability of collision between the two, and the spray dust reduction technology is often required to achieve higher atomization efficiency.
At present, there are many studies at home and abroad on improving the efficiency of atomization dust reduction, but there are few studies on supersonic atomization dust reduction technology, especially the improvement and optimization of liquid phase discrete mode and structural parameters according to the supersonic flow characteristics in the tube. To this end, supersonic siphon pneumatic atomization dust reduction technology is proposed, the design device is optimized and the characteristics of atomization dust control and on-site application are studied.
Excerpt
For a long time, the coal industry has been seriously harmed by high-quality concentration of respiratory dust, and conventional wet dust removal methods are not targeted, the capture efficiency is low, the energy consumption is high, and the reliability is poor. In order to solve this problem, the supersonic siphon pneumatic spray dust reduction technology is proposed, and the particle size distribution of the outer fog field is determined by using the principle of Furang Hefei diffraction, and the particle size and fog field velocity distribution characteristics of the near-field fog droplets at 0-30 cm at the nozzle outlet that cannot be obtained by the test method are simulated by using the finite element method of computational fluid dynamics, and the near-field fog droplet particle size and fog field velocity distribution characteristics at the nozzle outlet that cannot be obtained by the test means are simulated.
Through the dust control comparison test with the ultrasonic dry fog dust suppression technology, the dust control characteristics and dust control mechanism of the technology were obtained, and the influence of different working conditions parameters and nozzle outlet taper on atomization energy consumption and dust reduction rate was obtained through experimental research, and the research results showed that:
The designed atomization dust suppression device achieves the micron-level and high-power atomization effect of negative pressure water siphon under aerodynamic pressure as low as 0.2 MPa. At aerodynamic pressure of 0.6 MPa, the particle size distribution range of the fog field is 1.00 to 21.87 μm, and the number concentration of droplets below 10 μm in the near field area of the nozzle accounts for 90% of the droplets below 10 μm and 80% below 5 μm; the droplet velocity is fast and the range is long, and the number concentration of the droplet velocity of more than 160 m/s accounts for 50%, and the number concentration of fog droplets above 160 m/s accounts for 50%, and the number concentration of fog droplets above 50 m/s accounts for 99%.
The air consumption and water consumption are low, and when different working conditions and opening taper, they increase with the increase of aerodynamic pressure; the spray angle is within 60 ° ~ 95 °, and the nozzle cone angle is increased first and then decreased. The dust reduction rate is 1.5 times that of the ultrasonic dry fog dust suppression method, and increases with the increase of the concentration and speed of the number of fog droplets, and the instantaneous efficiency is increased by 2% to 26%; when the same dust reduction efficiency, the proportion of dust below PM10 on the sampling filter membrane is reduced by 24%; the dust insulation effect is increased by 10%. After the application of the 06 return wind lane of Mindong No.1 Mine, it is disturbed by the wind flow with a central wind speed of 0.86 m/s, and it can still penetrate and cover the full section, and the dust reduction efficiency of respiratory dust has reached more than 88.8%, which proves that the atomization system can achieve low humidity, water saving and efficient dust control effect.
Image
Mechanism of transverse jet atomization of supersonic flow field
The principle of transonic flow within a Laval nozzle
Internal flow characteristic distribution of Laval nozzles
Structure and atomization mechanism of supersonic siphon siphon aero-atomization device
Supersonic water siphon aerodynamic atomization effect
Droplet particle size V50 test results
Meshing and axial mesh refinement
Three-dimensional distribution of near-field droplet velocity size
Fog droplet velocity and quantitative concentration relationship statistics
Statistics on the number and concentration of particle size distribution under 100 micron fog droplets
Water extraction anti-blocking stability test process
Dust control test platform
Atomization angles of different outlet taper nozzles
The total energy consumption of the two nozzles is shown in contrast to the polyline
Supersonic siphon siphon atomization dust reduction mechanism
Full-section supersonic water siphon screen effect
About the Author
Zhang Tian, male, born on August 26, 1992, Fuxin, Liaoning, doctor of engineering, deputy supervisor of master's students, lecturer of the School of Safety Science and Engineering of Liaoning Technical University, member of the first batch of "double first-class" discipline construction innovation team members of Liaoning Technical University, youth member of the Ventilation Safety and Health Professional Committee of the China Occupational Safety and Health Association, researcher of the Engineering Protection Training Base of the Occupational Health Research Center of the National Health Commission. He has participated in 7 longitudinal project research projects such as the National Natural Science Foundation of China, the Natural Science Foundation of Liaoning Province, and the Liaoning Provincial Department of Education Fund, and 7 horizontal projects entrusted by enterprises. He has published more than 10 academic papers, including 6 SCI and EI searches, and 3 authorized invention patents.
Research Directions
Occupational safety and health engineering, mine ventilation and dust control
Key results
It is committed to the research of supersonic coaxial aerosol spray, pneumatic cyclone jet spray, spiral pneumatic spray, water mist induction charge, negative pressure coil suction curtain, magnetization and chemistry and other technologies and their dust control mechanism and application. The spray dust reduction technologies such as supersonic siphon pneumatic atomization, supersonic coaxial aero atomization, supersonic cyclone dynamic jet, supersonic aerodynamic spiral, and water mist induction charge are proposed, and the corresponding atomization device and the corresponding spray dust reduction system are developed, and the application effect is good in coal mine wells and coal preparation plants.
source:
ZHANG Tian,JING Deji,GE Shaocheng,et al. Supersonic Siphon Pneumatic Atomization Dust Reduction Technology[J]. Journal of China Coal Society,2021,46(12):3912-3921.]
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