Numerical simulation of the minimum mine dust exhausting wind speed under high altitude environment

In order to reduce the dust pollution during mining at high altitude mine,improve the effect of dust removal by ventilation and reduce the danger of mine dust to operators,a theoretical model of minimum dust exhausting wind speed has been established by the distribution law of wind flow in the roadway and the force applied on dust based on the turbulence characteristics of the circular tube.According to the change of environmental parameters caused by the altitude increase,the dust exhausting wind speed is quantitatively analyzed.According to the measured results,taking the No.6 exploration roadway of layer 4490 of Jiama Mine in Lasa as the research background,the ventilation and dust removal model for the heading face is established using Soildworks and ANSYS.On the basis of the simulation results of the wind flow,the dust trajectories of various particle sizes at different altitudes are simulated.The results show that the dust diffuses forward under the carrying effect of wind,and the smaller the particle size,the farther the diffusion distance.When the environmental parameters change after the altitude increases,the force applied to the dust particles changes and the movement state also changes.Under the same wind speed,especially for the respirable dust,when the altitude increases,the particle sedimentation rate increases,the diffusion distance becomes shorter,and the dust mass flow rate in the wind flow decreases.It is difficult for the wind speed of 0.25 m/s to carry all the dust out of the working face,resulting in the possibility of secondary dust contamination.Therefore,the dust exhausting wind speed in the plateau mine should be adjusted with the change of environmental parameters.Therefore,in order to exhaust dust from the heading face,the variation of the respirable dust concentration along the heading face under different wind speeds at various altitudes is analyzed,and the minimum dust exhausting wind speed at different altitudes are obtained.Comparing the simulation results with the theoretical model,the error is less than 3%,so the model can be used to determine the minimum dust exhausting wind speed at different altitudes,so as to calculate the wind demand of the plateau mine.