Influence Of Heat From Air Leakage In Goaf On Thermal Environment Of High-temperature Coal Mining Face

The heat disaster of coal face is a common disaster in high temperature coal mine,which seriously threatens the health and safety of workers.In order to solve the problem of heat damage in working face,before taking engineering cooling,we should first find out the source of heat damage in working face and provide reasonable cooling basis for heat damage control.When considering many heat sources in coal face,air leakage and heat dissipation in goaf is an important heat source that can not be ignored.Air leakage in the goaf will bring high temperature tropics into the working face and aggravate the problem of heat damage.On the one hand,the air leaked from the goaf exchanges heat with the high-temperature coal rock,and the air temperature will rise and flow into the working face;on the other hand,the air leakage in the goaf is easy to cause the coal spontaneous combustion,which will cause the coal rock temperature to rise,and generate high-temperature gas to flow into the working face with the high-temperature air flow.According to the porosity distribution and evolution characteristics of the mined-out area,and the law of spontaneous combustion and heat release of the coal in the mined-out area,a spontaneous combustion temperature field model of the mined-out area under the dynamic advancement of the mining face is established.Taking 401101 working face and goaf in Mengcun Mine as the research object,the effect of low-temperature oxidation and heat release of coal left in goaf on the thermal environment of mining face under different advancing speeds of goaf is studied;when the coal spontaneous combustion of goaf reaches a higher temperature,The law of the change of the wind temperature at the mining face;study the effect of the rock temperature on the working face thermal environment at the goaf;combine the study of the effect of the hot wind at the goaf on the thermal environment of the coal mining face,and simulate the status of the wind temperature at the mining face and the mining face Prediction of the improvement of mining face thermal environment at different inlet temperatures.The results show that under normal propulsion speed,the coal oxidation heat release in the goaf has little effect on the wind temperature of the mining face.When the mining face is propelled at 2.4 m/d,the average temperature of the working face only rises by 0.3?,and the temperature at the return corner 0.6? higher;when spontaneous combustion occurs in the mined-out area(up to 70?),the wind temperature of the return corner is nearly 1? higher than when it is not affected by coal spontaneous combustion.After spontaneous combustion of the coal in the mined-out area enters the rapid reaction period,the face wind temperature begins Accelerate the rise,the wind temperature rises more than 1?;the coal rock temperature in the goaf has a great influence on the heat leakage of the air leakage in the goaf.When the coal rock temperature in the goaf is 29? and 37?,the return wind corner wind When the temperature difference is 2?,and the temperature of the coal rock rises by 1? every time,the temperature at the return corner will increase by nearly 0.2?;the heat from the goaf of 401101 mining face of Mengcun Mine accounts for about 21%of the heat of the heat source of the mining face;When the inlet air temperature of the mining face is 24?,the average temperature of the working face can be reduced to 25.5?,which can effectively improve the thermal damage of the working face.According to the prediction results and the actual situation of the mining face,the mobile air cooling and cooling plan of the mining face is selected.Studying the air leakage and heat emission from the mined-out area can provide a basis for the temperature reduction of the high-temperature coal mining face project,and is of great significance for improving the thermal environment of the face and ensuring the safe and efficient production of coal mines.