| Coal transport is not only the necessary process in a coal mine,thermal power plants and other workplace,but also one of the most important dust resource.The dust is diffused into the material transportation system influenced by the entrainment of induced airflow,resulted in operating space dust pollution.At present,the research of dust control is mainly focused on the improvement of dust reduction methods and dust reduction measures,and the studies of the induced air flow from the theoretical and experimental point of view is seldomly.Study on the migration of induced airflow and dust diffusion in transfer point,by means of combining theoretical analysis,CFD numerical simulation and experimental research,analysis the induced airflow speed and the dust concentration under different conditions.It is found by experimental research:under the experimental conditions,as the amount of material increases from 0.56kg/s to 3.06kg/s,the maximum airflow velocity at chute is increased by about 80%,the maximum velocity of air flow induced by guide trough is about 76%,induced air speed and the feeding amount is greater than the base 1 logarithm function relation,environmental dust pollution aggravated;The dip angle of the chute is increased from 30 to 60 degrees,the speed of chute induced air flow increased from 0.95m/s to 1.18m/s,the air velocity induced by the guide trough increases from 0.55m/s to 0.75m/s.Within the experimental range,the induced air flow is linearly related to the angle of the chute,and the amount of dust increases continuously;according to the law of conservation of energy,the drop of coal is a process of transforming potential energy into kinetic energy,as height difference increases from 0.75m to 1.35m,the maximum velocity of chute induced air flow is about 89%,the maximum increase in airflow velocity induced by the guide trough is about 94%,tnd the induced airspeed is different from the height difference in power function;Tthere is a difference between the speed of induced air flow and the speed of belt,tnd the difference in velocity is greater,the friction between the surface of the coal and the surrounding air is more obvious,the greater the induced air velocity,the more serious the dust pollution in the transfer point environment.It is found by CFD numerical simulation and experimental comparison,the experimental results are basically consistent with the simulation results.With the increase of the amount of coal material,the velocity of the induced air flow increases,induced air speed and the feeding amount is greater than the base 1 logarithm function relation,The concentration of the dust is exponential with the amount of the material.With the increase of the dip angle of the chute,the induced air velocity in the guide trough increases,and the induced air velocity is linearly related to the angle of the chute.The angle of the chute increases and the intensity of the dust increases,under the experimental conditions,the induced air velocity and dust emission increase with the fall height difference,and the induced air flow and the amount of feed were two linear correlation,The material height difference is the main factor that influences the induced air flow;When the amount of material is cut and the height of the material is lower,the belt speed is greater than the induced airflow velocity,the effect of belt operation on induced air flow is obvious,the belt speed is less than the induced airflow velocity,the effect of the belt on the induced air flow is weakened,the increase of the induced air flow slows down,the amount of fugitive dust increases with the increase of belt speed. |
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