Multi-field coupling numerical study of coal spontaneous combustion in U-shaped stope dynamic advance

Abstract

In order to solve the problem of spontaneous combustion of coal in U-shaped stope during dynamic advance, a multiphysical field coupled mathematical model including the inlet and return airway, working face and goaf is established, and the reasonableness of the model is verified by field measurement data. The simulation analyzed the law of temperature field and oxygen concentration field in the goaf with the dynamic advance of working face, and further studied the influence of surrounding rock temperature, air flow temperature and working face advance speed on the self-heating of coal oxidation in the mining area. The results indicate that the temperature field on the inlet side of the goaf forms the phenomenon of high temperature region tailing in the shape of “wing section” in the process of advancing the working face, and the temperature of the high-temperature area gradually decreases under the effect of compaction of the goaf and heat dissipation of the surrounding rock; the temperature in the goaf continues to rise after the stoppage of mining, but the high-temperature area migrates to the working face; in the early stage of mining, different ventilation temperature has almost no effect on the maximum temperature in the mining area, while in the later stage of mining, the higher the ventilation temperature, the higher the maximum temperature in the mining area; the faster the working face advances, the lower the maximum temperature in the mining area.

Keywords

• u-shaped stope
• spontaneous combustion of coal
• dynamic advance
• concentration field
• temperature field