Coupling Mechanism Of Coal Spontaneous Combustion And Partition Seepage

In order to more effectively predict spontaneous combustion in the goaf of coal mines, this paper conducted experimental research on coal oxidation at low temperature based on the improved temperature rise experimental system for coal oxidation. The concentration variation law and oxygen consumption rate characteristics of C1and C2gases of coal at different granularities were obtained. And on the basis of the variation law of characteristics gases at different temperature, decision-making technique for spontaneous combustion of coal is materialized. By analyzing the experimental results, spontaneous combustion-related parameters of goaf for the purpose of numerical simulation were derived. By selecting bulk coal body as the research object, the bulk coal samples of five different granularities were prepared. By using the self-developed seepage coefficient measuring equipment, the seepage experiment on the bulk coal body was conducted. In analyzing the linear and nonlinear seepage characteristics of the gas in the bulk body, Darcy and non-Darcy seepage criteria are proposed, and the model for the relationship among permeability, porosity and granularity is established. In consideration of nonlinear characteristics of seepage near the working face in goaf in the process of stoping, and according to nonlinear seepage theory, spontaneous combustion mathematical model for the seepage zones of goaf is established by using Fick’s law and Fourier Law. Using the independent numerical computation program for spontaneous combustion of goaf, the similarities and differences between zonal seepage and non-zonal one are comparatively analyzed. Moreover, the site application was carried out. The simulation results indicate that, seepage in goaf is divided into linear and non-linear zone, near the goaf, Forchheimer model is complied with, and the depth of goaf conforms to Darcy Law. The research results of the dissertation provide theoretical basis and scientific grounds for prevention and control of spontaneous combustion in goaf.