Study On The Characteristics Of The Piston Wind And The Influence On The Stability Of The Ventilation System In The Underground Mine Tunnel

With the problem of increasing difficulty and instability of mine ventilation caused by the gradual extension of mining depth has become increasingly serious.Orbital transport occupies the first place as an auxiliary transportation system for mines,the piston effect caused by the movement of transportation equipment in the lane makes the air flow in the lane constantly change and presents a strong transient,which has a certain effect on the stability of the ventilation system.To effectively prevent and control underground disasters is inseparable from the stable and reliable ventilation system.How to ensure the safety and health of underground working environment is one of the difficult problems in mine ventilation.Therefore,it is of great significance to understand the correlation of the influence factors and the change of the ventilation resistance,so as to ensure the stability of the ventilation system and reduce the ventilation resistance of the roadway.In this paper,the corresponding mathematical physics model is established according to mine ventilation theory,computational fluid dynamics,aerodynamics,conservation of energy and piston wind effect,and calculate the calculation factors of piston wind in lane under different operating conditions of mine car by theory.The relationship between piston wind and influencing factors was simulated and analyzed by FLUENT fluid dynamics software,the SPSS software is used to analyze the correlation between the factors and determine the sequencing of the influence factors of the piston wind.Taking the roadway of a metal mine as the measurement object,the influence of the different running state and length of the mine car on the ventilation resistance and wind resistance of the tunnel is studied.The main conclusions are follows:(1)Theoretical analysis shows that regardless of the ventilation in the lane,the operation of the transport equipment will produce a piston effect.The size of the piston wind is related to the ventilation wind speed in the lane?the speed of the tramcar?the running state of the tramcar?the length of the tramcar? the blockage ratio?the total length of the tunnel and other factors,the piston effect on the stability of mine ventilation system has some dip.(2)The numerical simulation shows that the piston wind velocity produced by the running of the mine car is inversely proportional to the ventilation wind speed in the lane,the greater the ventilation wind speed,the smaller the piston wind and the less the piston effect.The piston speed of the tramcar is directly proportional to the blockage ratio two times.The greater the blockage ratio,the greater the piston speed in the lane and the stronger the piston effect.The piston wind speed produced by the mine car is directly proportional to the running speed of the miner,the greater the speed of the miner's running,the more obvious the piston effect,the greater the wind speed of the piston.(3)The correlation analysis shows that the piston wind speed is positively correlated with the running speed,and it has a negative correlation with the ventilation wind speed in the lane,which is positively correlated with the blocking ratio.the correlation coefficient of Pearson is: the running speed is 0.816,the ventilation velocity in the lane is-0.667,and the obstruction ratio is 0.029..The order of the degree of piston wind strength is: running speed> ventilation speed in the lane> blocking ratio.(4)The measurement of the mine shows that the effect of the running state of the mine car on the resistance and the total resistance of the total wind resistance is: running speed > the ventilation wind speed in the lane > blocking ratio;the greater the length of the mining car;The greater the length of the mine car,the greater the ventilation resistance and the total wind resistance,the more obvious the piston effect in the lane.The research results of the dissertation can provide theoretical basis for how to effectively control the piston effect of mine roadway and provide technical guidance for reducing the wind speed of piston in equipment operation.It is of great practical significance to ensure mine ventilation system stability and ensure mine safety and normal operation.