Research On Dust Distribution Law And Comprehensive Prevention Technology Of Rapid Tunneling Working Face

With the research and development of mechanized mining technology in coal mines and the use of new tunneling equipment,the rapid tunneling working face derived from the fully mechanized tunneling face appears.As the tunneling speed of the rapid tunneling working face is accelerating,the amount of dust generated has increased sharply,and it is severely spread in the roadway.The high concentration of dust not only threatens the health of mine workers,but also hinders safe and efficient production operations.Therefore,it is of great significance to study the high-efficiency dust-proof of the fast tunneling face.Based on the optimization of the long-pressure and short-extraction ventilation dust removal system in the rapid tunneling working face by the method of combining theoretical analysis and numerical simulation,this paper proposes a multi-negative pressure air duct dust removal system and a wall-attached air duct dust control system,and discussed the structural characteristics and parameter optimization of the spiral-outlet type wall-attached air duct and radial-outlet type wall-attached air duct.Based on the theory of gas-solid two-phase flow,this paper uses ANSYS Fluent numerical simulation software to simulate the dust distribution of rapid tunneling working face.Perform on-site verification and get the following conclusions:(1)The simulation of the air flow in the roadway shows,the long-pressure and short-extraction ventilation in the rapid tunneling roadway will form a vortex zone before and after the windlass,which hinders the removal of dust.Through reasonable air duct layout and air volume ratio,dust accumulation can be reduced and dust removal efficiency can be improved.(2)After parameter optimization through numerical simulation,it is concluded that when the diameter of the positive-pressure air duct is 1m,the distance from the working face is 15m,the diameter of the negative-pressure air duct is 0.8m,the distance from the working face is 3m,and the pressure-extraction ratio is 1.3,the dust removal efficiency of the long-pressure and short-extraction ventilation and dust removal system is higher.On this basis,optimizing the and short-extraction ventilation and dust removal system is higher.On this basis,optimizing the suction tube can increase the range and intensity of negative-pressure air duct,and further reduce the dust concentration.(3)The air curtain formed by the wall-attached air duct can control a large amount of dust in a certain range working face,improve the driver's working environment,block the spread of dust,and compress the dust source dust injection space.Compared with ordinary long-pressure and short-extraction ventilation,the wall-attached air duct can show better dust control effect.(4)Using the controlled variable method to ensure that the parameters of the long-pressure and short-extraction type remain unchanged,the width of the outlet opening and the air distribution volume of the spiral-outlet type wall-attached air duct and radial-outlet type wall-attached air duct are optimized.Through the comparison of numerical simulation results,it is concluded that the best outlet widths of the spiral-outlet type wall-attached air duct and radial-outlet type wall-attached air duct respectively are 0.3m and 0.05m,and the radial-to-axial air outlet ratio is 1:2.According to field verification,the dust is effectively controlled within 3m working face.