| Mine ore pass mostly near the pit-bottom station,or near the side of the wind drift,more and more underground mining going in deep mining,as the increasing height of ore pass,shock airflow and dust pollution is becoming more and more serious.due to the limitation of narrow space,broken ore will compress the air of ore pass in the process of falling,form is similar to the movement of the piston,the increase in height of ore pass made the air compression and generate greater dynamic pressure sharply,in turn,more powerful shock airflow was generated,the dust with airflow form the wider spread through the bifurcation discharge chute and ore cavern,then ore cavern room and around roadway was serious polluted,and even cause the pollution of ventilation system.However,the research on the shock airflow control of orepass is of great significance.This paper took the ore discharge process of the orepass as the research object,based on the piston wind aerodynamic basic equations and mines piston wind calculation model,established the shock airflow physical model and mathematical model;and expounds the control equation of discrete method and numerical method;Using FLUENT software dynamic grid module to simulate and analysis the various influence factors of the shock airflow,such as the height,quantity,frequency and orepass cross section size,the 3-d numerical simulation was used to Analysis of the flow field,pressure field and the shock airflow change law of Chute wellhead,and then used the measured data to verify with simulation results;Finally summed up the current orepass shock airflow control method,Adopt the method of simulation to verify the feasibility of sealed and pressure relief wells pressure release.The results show that:When ore discharge,blockage ratio belowed 0.25 was good for lowering the shock air flow,namely,increasing orepass cross section size or decreasing one-time ore quantity could reduce the shock air flow;shock airflow were linearly associated with the ore discharge height,sectional orepass or stepped orepass was beneficial to reduce the shock airflow;Multi-stage simultaneously ore discharge,air pressure produced by ore falling from different stages will happen superposition or offset,the simulation results show that Separated one stage ore discharging was helpful to reduce the shock airflow.in the process of ore in falling,in the process of ore in falling,ore front formed a positive pressure area,ore back-end form a negative pressure area,the pressure difference With the increase of the falling ore speed,the orepass internal airflow field can be divided into the inrush flow area which near the top bifurcation deviated chute,the reverse flow region which between orebody and borehole wall,vortex flow area which in the ore back-end and the slip wellhead flow area which near the bifurcation deviated chute which near the bottom bifurcation deviated chute;in the all orepass shock airflow control measures,wellhead sealing way has good effect on reduce shock airflow for orepass which below 300m and do not affect the orepass structure stability;It has the same great effect to use the pressure relief way to reduce orepass shock airflow,but for orepass shock airflow management work,should follow the guideline of comprehensive treatment,norm the design,strengthen management of ore discharge,take the joint governance approach. |
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