scholarly journals Dust Concentration Changing Regularities and Dust Reduction Technology by Spray Negative Pressure in Fully Mechanized Mining Face

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-16
Author(s):  
Lirong Wu ◽  
Hongxuan Chen ◽  
Jiamin Li ◽  
Shican Fu ◽  
Yuyan Zhuang
Keyword(s):  
Negative Pressure ◽  
Flow Characteristics ◽  
Dust Concentration ◽  
Inlet Section ◽  
Coal Face ◽  
Dust Suppression ◽  
Mining Face ◽  
Dust Distribution ◽  
Dust Reduction ◽  
Ventilation Velocity

The dust concentration changing regularities are the basis to take dust depression measures, which is greatly influenced by the airflow. In the software of FLUENT, the value of ventilation velocity is set as a constant, which cannot express the real ventilation. According to the flow characteristics of the sublayer and data from Nicholas’ experiment, the ventilation velocity distribution formula of sublayer in the inlet section of fully mechanized caving coal face is deduced. The boundary condition of velocity is given by UDF. Taking the 3top1110 fully mechanized caving coal face as an example, the dust distribution in the process of coal mining and hydraulic support shifting was studied. According to the dust-spray coupling experiment, three types of nozzle are chosen based on the efficiency of dust suppression. Combining the dust migration rule and the characteristics of nozzles, the negative pressure-secondary dust suppression devices of spray were developed and applied. And the above measures have lowered the dust concentration effectively.

scholarly journals Experimental Research and Numerical Simulation of Ejector Precipitator in a Fully Mechanized Mining Face

2020 ◽  
Vol 45 (11) ◽  
pp. 9815-9833
Author(s):  
Guodong Zhai ◽  
Wentao Zhang ◽  
Yaozong Li ◽  
Xinghao Lu ◽  
Wenyuan Hu
Keyword(s):  
Numerical Simulation ◽  
Flow Field ◽  
Negative Pressure ◽  
Coal Dust ◽  
Structural Parameters ◽  
Dust Concentration ◽  
Dust Removal ◽  
Measuring Point ◽  
Mining Face ◽  
Supply Water

AbstractIn order to effectively reduce the coal dust concentration in a fully mechanized mining face, this research used laboratory experiment, numerical simulation, and field test to conduct an in-depth exploration of the ejector precipitator installed at the low-level caving coal hydraulic support. Firstly, through the experimental platform in the laboratory, the dust removal effect of the nozzle with different structural parameters was tested, and the 3D particle dynamic analyzer was adopted to verify its atomization characteristics; then, the structural parameters corresponding to the nozzle in the best test results were obtained. Secondly, by using Fluent, the negative pressure flow field in the ejector barrel was numerically simulated. The results indicated that when the pressure of supply water was 12 MPa, the negative pressure value formed in the flow field was the lowest and the inspiratory velocity was the largest, which was conducive to dust removal. Finally, the tests of liquid–gas ratio and dust removal ratio were carried out in a fully mechanized mining face. The results showed that when the nozzle specification recommended by the experiment and the pressure of supply water recommended by the numerical simulation were used, the removal ratios of the total coal dust and the respirable coal dust were 89.5% and 91.0%, respectively, at the measuring point of the highest coal dust concentration. It indicates that the ejector precipitator has a good application effect in reducing the coal dust concentration in a fully mechanized mining face and improving the work environment of coal mine workers.

A novel spraying/negative-pressure secondary dust suppression device used in fully mechanized mining face: A case study

2016 ◽  
Vol 103 ◽  
pp. 126-135 ◽  
Author(s):  
Wen Nie ◽  
Xiao Ma ◽  
Weimin Cheng ◽  
Yanghao Liu ◽  
Lin Xin ◽  
...  
Keyword(s):  
Negative Pressure ◽  
Dust Suppression ◽  
Mining Face

scholarly journals Research on Dust Suppression Technology of Shotcrete Based on New Spray Equipment and Process Optimization

2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Pengcheng Li ◽  
Zhi Zhou ◽  
Lianjun Chen ◽  
Guoming Liu ◽  
Wei Xiao
Keyword(s):  
Process Optimization ◽  
Dust Concentration ◽  
Wind Pressure ◽  
Respirable Dust ◽  
Dust Production ◽  
Dust Suppression ◽  
Small Section ◽  
Root Cause ◽  
Dust Sources ◽  
Dust Distribution

In order to reduce the dust hazard of shotcrete, the paper analyzed the mechanism of dust production from the perspective of various dust sources and developed the plunger-type wet spraying machinery and wet mixer which can be applied in the small-section tunnel for reducing dust on the root cause. The dust concentration between dry-mix shotcrete and wet-mix shotcrete was compared and analyzed. The results showed that the average total dust concentration and respirable dust concentration in the process of dry spraying were 99.4 mg/m3 and 52 mg/m3, respectively, while 9.8 mg/m3 and 4.08 mg/m3 in the wet-mix shotcrete process, and the average dust concentration decreased by more than 90% after applying new wet-mix shotcrete outfits. The clean zone of dust was divided according to the dust distribution. Finally, the dust suppression technology was optimized by using an accelerator and adjusting wind pressure and spraying angle. Results indicated that the application of the accelerator reduced the dust production efficiently; moreover, when the wind pressure was 0.2 MPa with 1 m spraying distance and 90° angle of spraying, the dust concentration and rebound reached the minimum.

Investigation on dust dispersion during support movement in a fully mechanized mining face and the technology with support frame enclosure dust control

2021 ◽  
pp. 095440892110311
Author(s):  
Jinming Mo ◽  
Wei Ma ◽  
Dandan Li ◽  
Sheji Zhang
Keyword(s):  
Wind Speed ◽  
Field Application ◽  
Dust Concentration ◽  
Dust Control ◽  
Average Wind Speed ◽  
Dust Source ◽  
Air Inlet ◽  
Support Frame ◽  
Site Field ◽  
Mining Face

A fully mechanized mining face is characterized by serious dust pollution and dust is a major cause of pneumoconiosis that haunts numerous miners. For a fully mechanized face having large mining heights, the main dust source in the pavement area is produced by the moving support frame. To reduce the amount of dust during support's movement, the distribution and dissipation of dust in this process were studied by combining numerical simulations with underground measurements. The results showed that with an increase of the distance from the air inlet, the wind speed of the sidewalk in the fully mechanized face first increased, then decreased, and finally increased again. At the position of the coal cutter, the highest wind speed was 1.78 m/s and the average wind speed of the roadway was about 0.8 m/s. The dust concentration at the dust source was >1000 mg/m3. An area with a high dust concentration and having a length of 15 m was formed on the rooftop, together with a 50 m long dust belt with a dust concentration of 300 to 450 mg/m3 in the pavement area of 10 m from the dust source. Beyond the 45 m radius from the dust source, the dust concentration was stable at about 250 mg/m3. Based on the dust production characteristics of the support frame, an enclosed dust-guiding device was designed and structure-optimized. Based on the on-site field application test results, it was found that the device has a satisfactory dust-guiding effect during support movement and the dust suppression rate near the dust source reached 94.8%.

Research on Dust Suppression of a Copper Mine Underground Middle Level Crushing Station

2013 ◽  
Vol 726-731 ◽  
pp. 907-912
Author(s):  
Zong Yin Duan
Keyword(s):  
High Pressure ◽  
Middle Level ◽  
Dust Concentration ◽  
Dust Suppression ◽  
Copper Mine ◽  
Safety And Health

With long-term mining and new orebodies proved to be in the deep, the dust concentration of each mine underground operation site increased sharply, which is a serious threat to safety and health of workers in workspace. In this paper, a high pressure spray technology was put forward for dedusting on a mine underground middle crushing station[, and achieved the desired dedusting effect.

scholarly journals Experimental and Numerical Analysis on Flow Characteristics in a Double Helix Screw Pump

Energies ◽  
2019 ◽  
Vol 12 (18) ◽  
pp. 3420 ◽  
Author(s):  
Weibin Zhang ◽  
Qifeng Jiang ◽  
Gérard Bois ◽  
Hong Li ◽  
Xiaobing Liu ◽  
...  
Keyword(s):  
Numerical Analysis ◽  
Double Helix ◽  
Flow Characteristics ◽  
Leakage Flow ◽  
Inlet Section ◽  
Screw Pump ◽  
Local Flow ◽  
Local Distortion ◽  
Urans Cfd ◽  
Pump Inlet

Experimental overall performances on a double helix screw pump are presented and discussed, focusing on the leakage flow for two different rotational speeds. A comparison between experimental and URANS CFD approaches is performed in order to check the CFD closure models’ validity. Some specific local flow characteristics are extracted from the numerical results which give explanations about leakage backflows inside the screws and local distortion at the pump inlet section.

Pressure distribution and flow characteristics during negative pressure wound therapy

2020 ◽  
Vol 29 (1) ◽  
pp. 32-36 ◽  
Author(s):  
Niklas Biermann ◽  
Edward K. Geissler ◽  
Eva Brix ◽  
Daniel Schiltz ◽  
Clemens Muehle ◽  
...  
Keyword(s):  
Pressure Distribution ◽  
Negative Pressure ◽  
Negative Pressure Wound Therapy ◽  
Flow Characteristics ◽  
Wound Therapy

Study of the Effects of Shearer’ Kinematic Parameters on on-Way Distribution of Dust on Coal Face

2011 ◽  
Vol 127 ◽  
pp. 400-405
Author(s):  
Xiao Huo Li ◽  
Shu Ming Liu ◽  
Zhi Long Huang ◽  
Wei Du
Keyword(s):  
Rotational Speed ◽  
Dust Concentration ◽  
Discrete Phase Model ◽  
Kinematic Parameters ◽  
Coal Face ◽  
Two Phase ◽  
Concentration Maximum ◽  
Discrete Phase ◽  
And Migration ◽  
Kinematical Parameters

In order to research the effects of shearer’ kinematical parameters on on-way distribution of dust on coal face, according to the theory of suspension gas-solid two-phase flow and the theory of cutting dust formation, mathematical model of on-way dust concentration was established, methods of determining parameters were given, dust migration was simulated by using the discrete phase model (DPM) in FLUENT, on-way distribution regularity of dust was found. According to calculation of the quantity of cutting dust at different hauling speed and different rotational speed of drum, dust migration was simulated and migration regularity was showed as follows: dust concentration of every point on a coal face increased as hauling speed decreased or rotational speed increased. In addition, with rotational speed increased, the position of concentration maximum moved a little along downwind.

Flow characteristics of a small moving bed downcomer with an orifice under negative pressure gradient

2009 ◽  
Vol 192 (1) ◽  
pp. 110-115 ◽  
Author(s):  
Hiroshi Nagashima ◽  
Toshifumi Ishikura ◽  
Mitsuharu Ide
Keyword(s):  
Pressure Gradient ◽  
Negative Pressure ◽  
Flow Characteristics ◽  
Moving Bed
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