Numerical Study Of Full Mechanized Face Under Controllable Circulating Wall-attached Swirl Ventilation

With the continuous improvement of the mechanization level of mine mining,the dust production of fully mechanized mining face is increasing,and it is difficult to prevent and cure.It is one of the main sources of dust hazard,which seriously endangers the health of the workers and affects the safety production of the mine.Traditional ventilation technology can reduce the concentration of harmful substances in the working face to a certain extent,but the dust concentration in the working face,especially in the driving machine,also is often severely limited.Therefore,it is of great practical significance to put forward a new ventilation method to reduce the dust concentration of working face and to improve the working environment of the fully mechanized mining face and ensure the safe production of the working face.In view of the shortage of long pressure short pumping ventilation in the traditional fully mechanized mining face,a new ventilation mode,controlled circulatory wall swirling ventilation,is proposed in this paper,which is a new type of ventilation with the theory of cyclone ventilation and controlled circulation wind.Through the field investigation,the physical model and mathematical model of the controllable circulating wall swirling ventilation are established on the basis of the actual roadway size.The results show that the dust concentration at the inlet of the suction fan is not related to the pressure air volume when the dust removal efficiency of the dust fan in the tunnel is 100%.When the dust removal efficiency is 0,the dust concentration at the inlet of the suction cylinder is only related to the dust emission and air volume of the heading,but has nothing to do with the exhaust volume and the circulation rate.Through the numerical simulation of the attached swirling ventilation in fully mechanized mining face by using FLUENT software,the distribution of air flow and dust concentration in the roadway under different blowing and suction ratio conditions is compared and analyzed.The range of optimum blowing and suction ratio is obtained.By using the similarity theory,the physical model of the controllable cyclic wall swirling ventilation in the fully mechanized mining face is established.In order to control the dispersion of dust,a roadheader was introduced to simulate the diffusion law of dust in the fully mechanized working face.The PIV and dust measuring instrument are used to verify the reasonable blowing and suction ratio obtained in the numerical simulation.The conclusion is basically consistent with the numerical simulation results,and the correctness and feasibility of the simulation calculation are verified.Through the analysis of the factors affecting the effect of controlled circulating wall swirling ventilation,reasonable ventilation parameters of wall swirling ventilation are obtained.The results show that the air blowing and suction ratio is 0.8,the width of the slit air inlet is 0.06 m,and the ventilation effect is best when the slit air outlet is dispersed.At the same time,the effect of the dust control effect on the reloading point is changed,and the effect of the reloading point dust control efficiency on the dust concentration distribution of the fully mechanized mining flour is further analyzed.