| The coal industry has always occupied the main position in China’s energy supply industry,but the generation of dust in the coal mining process has brought great harm to the underground workers.The high concentration of dust in the underground coal mines has seriously damaged the health of underground workers,especially as one of the two major dust-producing places in the mine,the comprehensive excavation workings,due to the increased mechanization and fast digging speed,making dust pollution is also more serious,which This is a serious threat to the safety of mine production.In order to protect the occupational health and safety of coal miners and improve the working environment of coal mines,this paper takes this as the starting point to study the dust transport law of the heaving working face by means of field measurements,experimental analysis,theoretical analysis and numerical simulation,and to experimentally study the atomization performance of air-water mist nozzles with different characteristic structures,and finally,based on this,the air-water mist dust reduction technology is studied by using the method of similar simulation experimental research.The research was conducted.Firstly,the basic physicochemical properties of dust were carefully experimentally analyzed by field sampling,contact angle determination and infrared spectroscopy were performed on the samples,and dust dispersion was tested,and the Rosin-Rammler distribution function of dust dispersion was fitted,which provided calculation parameters for subsequent numerical simulations.Secondly,based on the examination of the site conditions at the 43311 heaving face of Changping mine,a geometric-physical model was established using Space Claim software,and a grid with high accuracy was delineated.Subsequently,three k-ε models of continuous phase were compared and differentiated,and the discrete phase method models were compared,and the mathematical model suitable for this heaving workface was preferably selected.Then,the dust transport law under the condition of single press-in ventilation was analyzed by FLUENT numerical simulation,and the distribution law of wind flow field and dust concentration field was obtained.Again,the effect of different spraying conditions on the atomization performance of the air-water mist nozzle was studied experimentally.Through the analysis of the results found that:the droplet particle size in the atomization area with the increase in the axial distance from the nozzle and increase,the radial direction size does not change significantly;when the water pressure is fixed,the atomization angle with the increase in air pressure is also increasing trend,the droplet particle size is decreasing trend;and when the air pressure in 0.8 ～ 1.2 MPa,water pressure in the range of 0.6 ～ 1.0 MPa,the nozzle atomization performance is more When the air pressure is in the range of 0.8～1.2 MPa and water pressure is in the range of 0.6～1.0 MPa,the atomization performance of nozzle is better,the atomization is uniform and the particle size is smaller.Based on the above research results on the dust distribution characteristics of the43311 excavation surface and the atomization performance of the air-water fog nozzle,the study of the effect of different atomization parameters of the air-water fog nozzle on the atomization of dust reduction was carried out,and it was found that the spraying conditions have a great influence on the efficiency of atomization of dust reduction: when the water supply pressure is kept constant,the efficiency of dust reduction by spraying gradually increases with the gradual increase of the air supply pressure;when the air supply pressure is constant,the efficiency of dust reduction by spraying gradually increases with the gradual increase of the water supply pressure.When the supply pressure is constant,the dust reduction efficiency varies in the process of increasing water supply pressure,but most of them show the trend of increasing first and then decreasing.The final results show that for this kind of basic characteristics of coal dust produced by 43311 heaving face: contact angle around 60° and high oxygen-containing functional groups,small particle size distribution,fine coal dust particles accounted for a relatively large,4# nozzle for its best dust reduction effect,the dust reduction efficiency of the whole dust can reach 89.34%,the dust reduction efficiency of respiratory dust can reach 76.45%,when its water pressure The water-pressure ratio is 0.8 MPa for water supply pressure and 1.2MPa for air supply pressure.These research results provide a reference data basis for the development of air-water mist dust reduction technology and theory. |
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