Study On The Piston Wind Effect Of The Main Air Intake (mixing) Shaft And Its Disturbance To The Air Volume Of The Transport Lan

The main intake shaft of a mine in Yunnan is also a lifting shaft.The piston wind effect caused by the frequent operation of large and efficient lifting cages in the shaft disturbs the air flow in the shaft.The main intake shaft is connected with multiple transportation roadways.The piston wind effect generated in the shaft will disturb the normal air flow transportation in the roadway and cause the phenomenon of air flow disorder.Therefore,this paper mainly studies the piston effect of double cage lifting in the main intake shaft and its disturbance effect on the air volume in the transportation roadway.The main conclusions are as follows:(1)The piston effect caused by the operation of double cages in the shaft is mainly affected by the ventilation velocity of the shaft,the running speed of the cage and the blockage ratio of the shaft.Combined with the correlation analysis,the theoretical regression equation of the maximum piston wind speed in this research model is:vmax=-4.347+1.350v0+0.250vt+14.019α,it shows that the piston effect in the shaft is affected by multi-factor coupling.(2)The local air volume loss of the transportation roadway caused by the shaft piston effect is mainly related to the eddy current zone generated by the cage operation.The larger the eddy current zone is,the more the air volume is lost.Under the influence of coupling piston effect,the probability density of longitudinal and transverse wind speed in the roadway is basically normal distribution.The variation trend of wind turbulence intensity along the longitudinal distribution is exponentially distributed.The change trend of the wind turbulence intensity value along the transverse distribution is symmetrically distributed along the center line of the roadway.The maximum value of turbulent kinetic energy Emax=0.351 m2·s-2 along the longitudinal distribution and the maximum value of turbulent kinetic energy Emax=0.4689 m2·s-2 along the transverse distribution are obtained in the roadway.The turbulent kinetic energy value is too large,which is easy to produce high and low speed air flow and eddy current in the local position of the roadway,and cause entrainment to the air flow.(3)Through simulation,it is known that the piston wind effect under the coupling effect in the main intake shaft leads to the total loss of air volume in each transportation roadway,accounting for 3.75%～5.08%of the total air volume of the mine,accounting for 4.55%～6.17%of the theoretical air volume of the mine,and the correction coefficient K3(K3∈[1.05,1.07])of the piston wind effect is obtained.Based on the task of the subject,this paper studies and solves the problem of air volume loss caused by the wind effect of the main inlet shaft double cage lifting piston;at the same time,this paper supplements and improves the local ventilation theory to a certain extent based on the research results of piston wind effect in similar mixed shafts.