Study On Optimal Regulation Rules For Best Dust Distribution Of Fully Mechanized Heading Face In Coal Mine

With the increasing of the mechianization in minjing and the production strength,the dust explosion accident and the risk of pollution have risen sharply.At present,the local ventilation control mode of the extensive "total quantity of air" of the fully mechanized mining face cannot change the airflows state at the air duct outlet:which cannot meet the dust reduction damand.It's very essential to change the angle,caliber and the distance from outlet to heading face,to realize the best regulation of dust distribution.In this paper,rough set theory,fluid mechanics theory,finite element numerical simulation technology and underground test verification method are used to study the acquisition method of airflow field regulation rules under different geometry size,angle,caliber and front and back distance of the outlet.Then the decision information system is established.The regulation rules is obtained and the airflow field regulation is expressed by using the disccrnibility matrix algorithm of attribute reduction and the hcuristic value reduction algorithm of rule acquisition,which provides the theoretical basis for the best dust distributi,on controlling.The specific contents are as follows:(L)Study on the obtaining method of the airflow field control rules when the dust is the best distribution.On the basis of the analysis of the dust distribution law and the controlling demand to airflow of fully mechanized.Ensuring the width of the tunnel,the outlet angle,the caliber and the front and back position of outlet as the condition attribute and the dust concentration as the decision attribute,the data acquisition and the discretization treatment is established,besides,the distinguishing moment of the attribute reduction is finished.The algorithm of matrix,the heuristic value reduction algorithm of rule acquisition and the expression of production rule arc analyzed.(2)Study on airilow field control decsion information system establishment.The numerical simulation scheme for the dust field is established.according to the actual ventilation situation in the fully mechanized mining face.Selecting the Ningtiaota as the object,the finite element model is established by using the FLUENT software.The dust distribution is simulated and analyzed,and the measured data of the dust concentration distribution is obtained.Then comparing the simulation results with the measure data,to verify the feasibility of numerical simulation scheme.According to the numerical simulation scheme of the dust field,the simulation experiments of airflow field under the different caliber of the outlet,the angle and the front and back distance parameters are designed.A lot of numerical simulated and analysis of the dust distribution under different parameters are carried out,and the initial decision information system is established.Combining the MDL algorithm and the equal frequency discrete methods,the discrete decision information system is established by discretizing the data in the initial decision information system.(3)Research on the airflow field regulation for the best dust distribution.The attribute reduction algorithm of the discernibility matrix is used to reduce the attribute of the discretized decision information system.The key condition attributes is obtained.The heuristic value reduction algorithm is used to reduce the redundant data in the key attribute decision information system,and the regulation rules of the airflow field are obtained.Realizing the dust reasonable distribution under different roadway space and different distance from outlet to heading face by changing caliber and horizontal deflection angle of the air duct outlet.(4)Analysis on the dust concentration distribution and the control effect of dust reduced The dust concentration distribution and dust reduction rate after the regulation of the airflow field at the nearest distance 5m and the maximum distance 10m are analyzed.The area of the dust concentration is greatly reduced,the accumulation phenomenon is reduced and the dust efficiency is obviously improved after the regulation,which provides the theoretical basis for the best dust distribution and dust reduced..