Experimental and simulation study on local positive pressure ventilation method to solve the low oxygen problem of mining faces
Aiming at the difficult problem of low oxygen phenomenon easily occurring in the working face of shallow-buried and contiguous seams,theoretical analysis,similar simulation,and numerical simulation were used to study.It is concluded that the geological conditions of coal seams,the ventilation method of working faces,the change of atmospheric pressure and the natural wind pressure are the main causes.And the feasibility of using the local positive pressure ventilation method to solve the problem of low oxygen in working faces was explored.The results show that when the negative pressure ventilation,the increase of ventilation wind speed does not significantly increase the oxygen volume fraction in the upper comer area of the working face,which is still less than 20％.And when the local positive pressure ventilation,the contour line of 20％oxygen volume fraction in the mining field is parallel to the working surface under the wind speed is 1.6 m/s,which effectively improves the oxygen volume fraction in the corner of the mining surface.And compared with the single local positive pressure ventilation,the method of adding air resistance to the return airway of local positive pressure ventilation can achieve the purpose of solving the low oxygen in the mining face under the condition of smaller wind speed.Meanwhile,it is beneficial to prevent the spontaneous combustion of coal left in the goaf.Using COMSOL simulation software,the stope gas migration model was established,and the oxygen volume fraction field distribution and migration law in the goaf under different ventilation methods and different wind speed conditions were carried out.Moreover,the numerical simulation results are almost consistent with the experimental measurement results.The field treatment of low oxygen in the working face 3105 of a mine in Shanxi Province has been carried out.The practice shows that the technical measures of using local positive pressure ventilation and increasing air resistance in the return air lane can effectively solve the low oxygen problem in the working face.And the oxygen volume fraction in the upper corner and return air flow of the working face increased from 15％to more than 20％,and always maintained the normal level,ensuring the safe production of the working face.
safety and hygiene engineering technologylow oxygen in working faceslocal positive pressure ventilationupper comergoafnumerical simulation
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万方数据
维普
