浅埋薄基岩自燃煤层火源位置探测数值计算及应用
Numerical Calculation of Fire Location of Shallow Buried Thin Bedrock Spontaneous Combustion Coal Seam and Application
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摘要: 数值计算方法是研究氡迁移机制问题常用的手段之一，以半无限大均匀多孔射气介质为计算模型，推导出氡在其中的运移传播方程，并分别计算了只有扩散或对流作用下射气介质表面氡运移及析出规律。计算结果发现，半无限大均匀多孔介质中氡浓度分布规律服从指数分布。在以扩散对流作用为主的氡迁移过程，射气介质的氡析出率取决于射气介质孔隙氡浓度大小及流体的对流速度。只在扩散作用下氡析出率的大小由孔隙浓度决定；只在对流作用下氡的析出率由流体流动方向和流速大小决定。将计算结果应用于测量浅埋藏薄基岩自燃煤层地表氡值，探测结果与理论计算结果吻合度高。Abstract: The numerical calculation method is one of the common means to solve problem of radon migration mechanism. In this paper, by taking a semi-infinite homogeneous porous radioactive medium as calculation model, we deduced propagation equation of radon migration, and calculate the surface radon migration and precipitation behavior of radioactive medium only by diffusion or convection. The results show that the radon concentration distribution law in semi-infinite large homogeneous porous medium obeys exponential distribution. In the process of radon migration based on diffusive convection, the radon exhalation rate of the radioactive medium depends on the concentration of radon in the radioactive medium pore and the convection velocity of the fluid. The radon exhalation rate is determined by the pore concentration under the effect of diffusion; and the rate of radon precipitation is determined by the direction of fluid flow and the velocity of flow under the action of convection. The results will be applied to the measurement of shallow buried thin bedrock coal seam surface radon detection results, and the calculation results agree with high degree of research results.
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