In order to explore the influence of rock block scale on the spontaneous combustion of coal in the fully-mechanized goaf,the Fluent software was used to numerically simulate the spontaneous combustion law of coal in the goaf under different diameters of rock block,and the oxygen concentration filed air velocity field in the goaf were analyzed.The oxygen volume fraction and air velocity were respectively taken as the index,then the oxidation zone area of goaf was determined and the two-field superimposed field was used as the standard for dividing the coal spontaneous combustion hazardous zone in the goaf,and the relationship between the coal spontaneous combustion hazardous zone and the rock block diameter was studied.The results show that when the diameter of rock block increases from 0 to 10 m,the width of oxidation zone decreases when the ox-ygen volume fraction is used as the index,and the area decreases from 5 563.84 m2 to 2 602.69 m2.Taking the air velocity as the index,the area of oxidation zone decreases from 3 376.60 m2 to 1 262.95 m2.The oxidation zone determined by the two indexes is superimposed to obtain the coal spontaneous combustion hazardous zone,and with the increase of rock block diame-ter,its area decreases from 1 854.04 m2 to 552.91 m.and its maximum width decreases from 20.40 m to 9.06 m.The research results can provide reference for the determination of the coal spontaneous combustion ignition area in the goaf.
rock block scalegoafoxidation zoneresidual coal spontaneous combustionnumerical simulation
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