关键词: 采空区, 自然发火, 无因次分析, 数值模拟

Abstract: Spontaneous combustion in gob is a complex process and studying on the variation and influence factors of airflow field and oxygen concentration field is the prerequisite to forecast high temperature in gob. Firstly, the mathematical model of flow field and oxygen concentration field under moving coordinates is established, and then the dimensionless form of the model is studied. At the same time dimensionless criteria such as dimensionless pressure, dimensionless velocity, dimensionless oxygen diffusion coefficient, and dimensionless oxygen consumption velocity coefficient are defined. Through analysis, residual coal thickness is an important factor of spontaneous combustion in gob. Finally, the distribution map of the oxygen concentration field under different thickness of the residual coal is obtained by numerical simulation, concluding that the distribution of oxygen in the goaf is wider with the thickness of the residual coal is decrease.