| The dust control measures of coal mine dust have been studied and solved in recent years.Dust brings hidden dangers to workers and production safety to varying degrees,especially the increase of pneumoconiosis and the continuous occurrence of industrial accidents.The most harmful dust produced in coal mining process is respiratory dust,which accounts for about 30%of the total dust concentration.If green mining can be realized,the harm will be reduced accordingly.Therefore,study the wind speed distribution of roadway,the theory of migration and settlement of small particle dust in roadway and its dispersion The regularity and deposition distance are of great reference significance for studying the calculation of dust removal and exhaust air volume,determining and placing the dust measuring points at the entrance of roadway and preventing and controlling dust.In this paper,the migration of small particle dust(mainly respiratory dust)in roadway is studied.Theoretical analysis and numerical simulation are used to find out the migration law of dust under different roadway wind speed.In the study,dust particles of the sizes of 2?m,5?m,10?m?15?m,and 0.15m/s,0.25m/s,1.0m/s,1.5m/s,2.0m/s,3.0m/s,4.0m/s,6.0m/s were selected for wind speed simulation.The length of 210m,width of 3.6m,height of 3.5m box roadway model were selected to simulate the movement law of dust in the wind flow,this paper explores the effect of ventilation and dust reduction by comparing the movement law of dust of different particle sizes in the well lane at different wind speeds.First,the state of the same particle size dust at the critical wind speed allowed by the two wells and alleys is simulated,with a view to simulating the other wind speeds.Critical wind speed when dust particles do not sink is also the focus of this paper.Through the simulation under these conditions,the relationship between concentration distribution and wind speed,concentration and particle size can be obtained,and the particle size distribution map and the distance-concentration curve can be obtained to visualize the motion trajectory of dust particles.According to the results,when the wind speed in the lane is 0.15m/s,the 2?m dust begins to subside at 20m along the course,while the 5?m dust begins to subside at 10m along the course,and the critical wind speed range of the two particle size dust does not sink is 1.5 to 2 m/s;When the wind speed is 2m/s,10?m of dust subsides at 130m along the way;When the wind speed is 3m/s,there is no subsidion along the 10?m dust,15?m dust at 125m,and at 4m/s there is no subsidy;then the critical wind speed range of 15?m dust does not subside is 3 to 4m/s while the critical wind speed range of 10?m dust does not sink is 2 to 3m/s.Compared with the field measured data of others,it is found that the trend of dust concentration migration is the same,which shows the rationality of parameter setting,and verifies the feasibility of numerical simulation and the reliability of simulation results.Figure[49]table[5]reference[90]... |
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