Influence of radial vortex migration in fully-mechanized mining roadway on dust pollution caused by coal cutting
In order to grasp the influence laws of the dynamic migration process of air curtain on the dust pollution caused by coal cutting in the fully-mechanized mining roadway,and further improve the dust blocking efficiency of air curtain,the flow field structure evolution and dust pollution of fully-mechanized mining roadway under different radial vortex intensities and migration distances were studied and analyzed by the combined methods of numerical simulation and on-site measurement.The results show that the radial vortices move in the form of wall-attached swirling flow.As the intensity and migration dis-tance of radial vortex increase,the tributaries biased towards the pressure side and axial direction are formed respectively dur-ing the migration process.Subsequently,the radial vortices gradually transform into a uniform axial flow field,and the dust pollution present the law of continuous decrease,and the law of increase first and then decrease,respectively.The relation-ships between the dust concentration at the excavation driver's location and the radial vortex intensity and migration distance satisfy the Boltzmann model and LogNormal model,respectively.When the radial vortex intensity is 0.9 and the migration dis-tance is 30 m,the efficient dust control can be achieved.On-site measurement show that the total dust and respiratory dust re-duction rates at the excavation driver's location reach to 82.7%and 78.3%,respectively,effectively improving the working environment for personnel.The research results can provide reference for efficient control and treatment of dust pollution in the fully-mechanized mining roadway of coal mines.
radial vortexwall-attached swirling flowflow field evolutiondust pollution
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