Numerical simulation study of spontaneous combustion in goaf based on non-Darcy seepage

Abstract

In order to study the influence of non-Darcy seepage on spontaneous combustion in goaf, seepage tests were conducted in three groups of broken rocks which were different average particle sizes, and then the test data were processed by non-Darcy seepage equation. So that the equations of non-Darcy permeability coefficient K with porosity n and particle size d, non-Darcy flow factor β with the n and the d were achieved. On the basis of these equations, the paper analyzed the influential factors of the spontaneous combustion in goaf, and then established the spontaneous combustion mathematical model on the coupling of air flow field, oxygen concentration field and temperature field on moving coordinates. According to the model, the calculating software was programmed by VB6.0 to obtain the oxygen concentration distribution map and the residual coal temperature distribution map in goaf. The results are of theoretical and practical significance to prevent spontaneous combustion in goaf.