动态推进U型采场煤自燃多场耦合数值研究

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

    • 摘要: 针对动态推进过程中U型采场的煤自然发火问题,建立包含采场进回风巷道、工作面与采空区的多场耦合数学模型,并通过现场实测数据验证了模型的合理性。模拟分析了采空区内温度场、氧气体积分数场随工作面动态推进的变化规律,并进一步研究了围岩温度、风流温度、工作面推进速度对采空区煤氧化自热的影响。结果表明:工作面推进过程中,采空区的进风侧温度场形成“机翼断面”形状的高温区域拖尾现象,并且高温区域在采空区的堆积压实和围岩散热作用下温度会逐渐降低;停采后采空区内继续升温但高温区域向工作面迁移;不同通风温度对采空区最高温度的影响,在开采的初期几乎无影响,而在开采的后期,通风温度越高,采空区内最高温度越高;工作面推进速度越快,采空区内最高温度越低。

       

      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.

       

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