Multi-field coupling laws of mixed gas in goaf

Residual coal in goaf easily causes spontaneous combustion, and provides a long-term existence fire source, then easily leads to secondary gas explosion. This paper has a systematic study on the laws of gas flow and heat transfer in goaf pre-and post residual coal spontaneous combustion by numerical simulation. Multi-field coupling changed laws of gas-air mixed gas 3D seepage field, concentration field and temperature field pre-and post residual coal spontaneous combustion in goaf have been obtained by discreting mathematical model equations. The numerical simulation results coincide well with site observation data.