采空区自然发火的多场耦合机理及三维数值模拟研究

发布时间：2019-06-11 02:37

【摘要】：采空区自燃火灾是井下重大灾害之一，也是矿山安全领域重点研究的问题。由于现场监测及相似模拟实验都存在难题，因而数值模拟成为研究采空区自然发火的主要手段。本文通过实验研究了氧浓度、粒度以及挥发份等对煤自燃的影响；分析了采空区内的产热与散热规律，提出了采空区自然发火的能量迁移理论，实现了采空区最高温度的理论预测；揭示了采空区自然发火的多场耦合机理与过程，建立了三维多场耦合数学模型；确定了四面体单元控制体的合理圈划方案，提出了精度很高的有限体积法新算法；利用新算法离散自然发火模型，，编制了“采空区自然发火的三维仿真系统”，结合河东矿31005工作面的现场参数，模拟得到了注氮前后的采空区自然发火情况，并分析了推进速度、遗煤厚度对自然发火的影响；现场布线观测了该采空区的温度变化，结果表明注氮参数选择合理，达到了防火目的；实测温度与模拟温度吻合较好，也说明数值模拟结果较为可靠。该成果将能在采空区自然发火的预测预报以及防火技术参数确定等方面得到应用。
[Abstract]:Spontaneous combustion fire in goaf is one of the major underground disasters, and it is also a key problem in the field of mine safety. Because of the problems in field monitoring and similar simulation experiments, numerical simulation has become the main means to study spontaneous combustion in goaf. In this paper, the effects of oxygen concentration, particle size and volatile components on coal spontaneous combustion were studied by experiments. The law of heat production and heat dissipation in goaf is analyzed, and the theory of energy transfer of spontaneous combustion in goaf is put forward, and the theoretical prediction of the highest temperature in goaf is realized. The multi-field coupling mechanism and process of spontaneous combustion in goaf are revealed, the three-dimensional multi-field coupling mathematical model is established, the reasonable delineation scheme of tetrahedral element control body is determined, and a new finite volume method algorithm with high accuracy is put forward. Using the new algorithm to discretize the spontaneous combustion model, a "three-dimensional simulation system for spontaneous combustion in goaf" is compiled. Combined with the field parameters of 31005 working face in Hedong Mine, the spontaneous combustion in goaf before and after nitrogen injection is simulated. The effects of propulsion speed and residual coal thickness on spontaneous combustion are analyzed. The temperature change of the goaf is observed by field wiring, and the results show that the nitrogen injection parameters are reasonable and achieve the purpose of fire prevention, and the measured temperature is in good agreement with the simulated temperature, which also shows that the numerical simulation results are more reliable. The results will be applied to the prediction and prediction of spontaneous combustion in goaf and the determination of technical parameters of fire prevention.
【学位授予单位】：中国矿业大学（北京）
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TD752.2

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