Study On Gas Migration Law In Goaf Of J-type Ventilation In Wangzhuang Coal Mine

The tail lane of J-type ventilation system will be deformed and damaged by the complex conditions of mine.Therefore,it is very important to study the influence of the change the tail area on the flow field and the gas distribution in the goaf,which is of great significance to the efficient use of J-type ventilation to solve the gas problem.In this paper,according to the actual caving of coal and rock in the 8103 working face of Wangzhuang coal mine,using the Fluent software,the pressure difference between the two ends of the working face is 246.5pa by numerical simulation,which is basically consistent with the filed measurement.Analysis on the flow field and gas migration law in goaf under different sectional area of tail lane in the fully mechanized coal face J-type ventilation,the results showed that in the J-type ventilation system,the wind flows along the working direction,and flows into the goaf from the lower corner to the upper corner.With the increasing of tail lane sectional area,air velocity and the quantity of air leakage is increased,the whole goaf area gas concentration is reduced,while the upper corner of the working area of the gas concentration is also constantly reduced.Through analyzing the law of gas concentration in the upper corner with area of tail lane changes is determined,when the actual working face into the air is2198m~3/min,to ensure the corner gas concentration in the safe range,the area of tail lane should not be less than 7.2m~2.In order to ensure the upper corner gas concentration in the safe range,the minimum amount of air intake is different when the area of tail lane is different.Respectively different area of tail lane,studying on the gas concentration in goaf and the upper corner gas distribution changes with air intake by numerical simulation.Analyzing the different area of tail lane to ensure the upper gas concentration in the safe range minimum air intake.The results show that:in order to ensure the safe production of the working face,when the area of tail lane is S=4m~2,the air intake should be guaranteed not less than 2950m~3/min;when the area of tail lane is S=6m~2,the air intake should be guaranteed not less than 2650m~3/min;when the area of tail lane is S=9m~2,the air intake should be guaranteed not less than 2100m~3/min;when the area of tail lane is S=12m~2,the air intake should be guaranteed not less than 1900m~3/min.