Study On Field Atomization Rule And Efficient Spray Dust Suppression Technology In Full-mechanized Mining Face Of Mine

The fully mechanized mining face is the main dust producing place in the whole mine production system.Due to the characteristics such as many dust producing processes and large dust production,the fully mechanized mining face has become one of the most difficult sites for dust control.Field measurements from several mines show when the shearer drum is cutting,the local concentration of dust is even more than 3000mg/m3,which seriously exceeds the standard and threatens the health and safety of mine workers.This paper mainly adopts the combination methods of experimental research,theoretical analysis,numerical simulation,field application and so on to explore effective ways to solve the problem of dust pollution in fully mechanized mining faces.The main contents and results are as follows:Based on the mechanism of dust suppression by nozzle,the spray model was established and the main factors affecting the dust capture by droplet were analyzed.The wind environment of the fully mechanized mining face in Bai Lu coal mine was simulated based on the experiment platform with multi-characteristics of spray field.Firstly,10 kinds of nozzles suitable for dust control in coal mine were tested to macro characteristics of spray field.The effective range,spray angle and flow rate of every nozzle and other macro characteristics were recorded and analyzed,respectively.The nozzle numbered as ? was selective preference.Secondly,the spray field concentration and other micro characteristics were analyzed by PDI phase Doppler laser interferometer.The datas show that the spray field concentration in the test area increases with the increase of spray pressure,but due to the influence of transverse wind,the spray field produced by the single nozzle is hard to meet the requirements of dust suppression by spray.Inspired by the effect of droplet transported by high-speed wind,an efficient spray dust suppression system,which consists of wind assisted centralized spray dust suppression device for hydraulic props and wet wind assisted dust suppression device for shearer,has been developed.By employing the FLUENT software,the simulated air flow was setted as 1.2m/s in 4307 fully mechanized mining face of Bai Lu coal mine,and then the spray and wind parameters of wind assisted centralized spray dust suppression device for hydraulic props and wet wind assisted dust suppression device for shearer were setted.The numerical simulation results show that after adopting the new spray dust suppression device,the spray concentration around the shearer drum,which is the main dust producing source in the fully mechanized mining face,increases obviously.The spray field effectively enwraps the dust producing source.By field application and test of the efficient spray dust suppression system,the full dust and respirable dust suppression rate at the shearer driver were as high as 89.1%,90.1%,and the two dust suppression rate at the advancing support workers were as high as 89.6%and 89.4%,respectively.Accordingly,the dust concentration is reduced to 97.3mg/m3,41.9mg/m3,75.5mg/m3 and 34.1mg/m3.It indicates that the dust pollution problem of cutting coal and advancing support procedure,which are the most serious and most influential workers in the production work in the fully mechanized mining face,has been effectively solved.