| As an important part of mine production development,single-head roadway excavation has the characteristics of difficult ventilation and easy accumulation of blasting smoke and dust.The study of CO distribution in gun smoke after blasting of single-headed roadway can understand the law of gun smoke movement with wind flow and the gun smoke concentration in different positions,which has practical significance for mine roadway excavation work.This paper uses theory to analyze the CO diffusion law after blasting in roadway excavation,conducts actual measurement of CO concentration in gun smoke in underground excavation roadway in metal mines,uses numerical simulation and orthogonal experiment method to study the influence of different factors on CO concentration distribution,and the main results are as follows:(1)For the summation of the smoke composition,the ventilation method of the tunneling face and the diffusion law of the smoke during the blasting of the roadway,a mathematical model of CO was established to summarize the CO diffusion law under the conditions of natural ventilation and partial press-in ventilation in the roadway.(2)The CO concentration in gun smoke at different positions after the blasting of the self-propelled iron ore tunnel was monitored,and the concentration decreased with the increase of ventilation time.The measured data at the monitoring point was fitted to the function equation of gun smoke concentration and time.(3)Establish a model of the tunnel monitoring area,use ANSYS Fluent to perform calculations,simulate the CO distribution law in the smoke,study the changes in the wind flow field and the CO concentration field,and conclude that the structure of the smoke belt is gradually stretched as the ventilation process progresses,and the CO concentration appears upward High and low distribution status.The reliability of the numerical simulation is verified by comparing the curve of the simulated value and the actual measured value over time.(4)The orthogonal test method was used to simulate the four factors affecting the CO concentration in the gun smoke,namely,the wind speed of the wind tube,the hanging height of the wind tube,the distance between the wind tube and the head of the tunnel,and the diameter of the wind tube.The 16 sets of simulation tests showed that the influencing factors are important The optimal air duct arrangement scheme is selected by using the range analysis method as the air duct wind speed is 13 m/s,height is 1.8 m,distance is 10 m,and diameter is 0.7 m.The reliability of the optimization scheme is analyzed by the gray correlation degree and verified by numerical simulation. |
