Multi-physics Coupling Mechanism And Three-dimensional Numerical Simulation Of Spontaneous Combustion Of Goaf

Spontaneous combustion of goaf is one of the major disasters underground and also the importantresearch problem for mine safety researchers. Due to the monitoring in field and the similarsimulation experiment in lab are existing problem, the numerical simulation become the mainresearch means for studing the spontaneous combustion of goaf. In this paper, the influence ofoxygen concentration, particle size and volatilization of coal were respectively studied on thespontaneous combustion by experiment, and the law of heat production and loss in goaf wasanalyzed by theory, so the energy migration theory of spontaneous combustion in goaf was putforward, which could predict the highest temperature of goaf in theory. The coupling mechanism andprocess of the spontaneous combustion of goaf in the flow field, oxygen concentration field andtemperature field was revealed, so as to establish the several fields coupling mathematical model inthree dimensional. A reasonable delimit plan for the unit control body of tetrahedron grid wasdetermined, so a new algorithm of the finite volume method was established in a high precision. Thenew algorithm was used to discrete the model of spontaneous combustion, and then the "SimulationSystem of Spontaneous Combustion in Goaf (3d)" was compiled to obtained the goaf spontaneouscombustion simulation before and after the nitrogen injection combined with the parameters of31005working face in Hedong Coal Mine, so the influence of advancing speed, thickness of the coalon the spontaneous combustion were got. The last, the temperature change of the goaf was observedin site and the results show that the effect of nitrogen injection was very good and the nitrogeninjection parameter was selected reasonably. What's more, the temperatures of the measured and thesimulated are coincidence, which show that the results of numerical simulation are reliable. Theresearch achievements will be applied in the spontaneous combustion prediction of goaf and theparameters selection of the fire prevention technology.