Research On Evolution And Early Warning Of Gas And Coal Spontaneous Combustion Symbiotic Disaster Based On Flow-Heat-Chemical Field Coupling

With the continuous demand for coal in the country’s economic and social development,the depth and intensity of coal mining continue to increase,and the constraints of high ground temperature,high ground pressure,high gas,and coal spontaneous combustion in the mining process have become increasingly serious.The gas gushing intensity increases,the risk of gas disasters increases,and factors such as air leakage and high temperature cause spontaneous combustion of coal left in the goaf,which is easy to induce gas combustion,explosion and other disasters;at the same time,the heat generated by gas combustion and explosion can cause coal spontaneous combustion,Disasters such as dust explosions lead to heavy casualties and property losses.The prevention and control of gas and coal spontaneous combustion symbiosis disasters has become an important topic that must be studied and effectively solved in the process of coal mine safety production.Therefore,it is necessary to study the coupling mechanism,evolution law,early warning mode and prevention technology of gas and coal spontaneous combustion symbiotic disasters.Aiming at the severity and particularity of symbiotic disasters,this paper adopts theoretical analysis,numerical simulation,comprehensive evaluation,system research and development and other research methods to discuss the coupling and evolution laws of symbiotic disasters,and provide theoretical and theoretical support for timely early warning and effective prevention and control of symbiotic disasters.Technical Support.The main research contents and results of the paper are:(1)Analyze the characteristics and coupling mechanism of symbiotic disasters.By analyzing the coupling mechanism of the two disasters,it is concluded that the symbiotic disaster is the result of the multi-field spatiotemporal coupling of the fissure field,the oxygen concentration field,the gas concentration field and the temperature field under complex spatiotemporal conditions.The coupling and evolution law of each factor under the condition of gas drainage are analyzed,and the division area of symbiotic disaster is obtained,which provides a theoretical basis for further analysis of the evolution process of symbiotic disaster.(2)Establish a multi-field coupling model for the evolution of symbiotic disasters.The fissures and air leakage mechanism in the goaf are analyzed,and it is concluded that the pressure difference of the working face,the hot air pressure and the gas drainage are the main factors causing the air leakage in the goaf.Combined with the theories of fluid mechanics,heat transfer,and porous media theory,a mathematical model of the coupled evolution of the flow-heatchemical field of the symbiotic disaster is established,and the key parameters such as oxygen consumption rate and heat release intensity required for the study are determined.(3)The evolution law of symbiotic disasters under different working conditions is obtained.Numerical simulation software is used to study the evolution law of symbiotic disasters under different inlet wind speeds and different ventilation modes,and obtain the distribution law of seepage field,gas concentration field,temperature field and symbiotic disaster area.The results show that: the use of buried pipe drainage reduces the gas accumulation in the corners of the working face;the inlet wind speed increases,the symbiotic disaster area of the goaf moves to the middle and deep parts,and the optimal wind speed that is conducive to suppressing symbiotic disasters is determined;The ventilation system and the reasonable location of the end lane can concentrate the symbiotic disaster area in the middle and deep part of the goaf,and have the effect of reducing gas accumulation.(4)Build a comprehensive early warning model for symbiotic disasters,develop early warning systems,and propose prevention and control measures.Based on the analysis of single disaster early warning model,a comprehensive early warning model of symbiotic disasters based on temperature field and concentration field is proposed.Based on the numerical simulation results and the early warning model,an early warning system for gas and coal spontaneous combustion symbiotic disasters in goafs is developed.The system can obtain the dynamic evolution law of gas and coal spontaneous combustion symbiotic disasters under different working conditions,and achieve the goal of early warning functions.Based on time,gas,oxygen,temperature and other elements,combined with the intelligent monitoring system of coal mines,a collaborative prevention and control system for symbiotic disasters is constructed.