1. College of Emergency Management and Safety Engineering, North China University of Technology, Tangshan 063210, China; 2. Key Laboratory of Mining Development and Safety Technology of Hebei Province, Tangshan 063210, China;
3. Kailuan Group Co., Ltd., Tangshan 063000, China
In order to reveal the correlation mechanism between heat transfer and oxidation heating in the process of coal spontaneous combustion, taking heated coal rock as the research object, combined with heat conduction theory and multi-physical field coupling method, the numerical model of thermal-hydro-chemical coupling was constructed by Comsol, and the kinetic equation of coal oxidation reaction and Darcy 's law were coupled to explore the regulation law of thermal conductivity, permeability and other parameters on the thermal accumulation of coal rock. The results show that the connectivity of coal-rock fractures is positively correlated with fluid flow and temperature, and negatively correlated with pressure. The more connected fractures, the better the heat transfer effect, and the pressure drop rate in the fracture zone is significantly higher than that in the non-fracture zone. The model has high accuracy verified by experiments, and the chain trigger mechanism of unsteady heat transfer on coal spontaneous combustion is explained. From the perspective of multi-field coupling, it provides theoretical model and simulation technical support for the identification of spontaneous combustion risk in goaf and the prevention and control of thermal dynamic disasters.
