Study On The Experimental And Numerical Simulation Of Thermal Characteristics Of Coal Oxidation Under Heat Flux

Oxidation of coal spontaneous combustion and high temperature heat flow in the process of coal mining is an important mining must face problem,closely related to each other between thermal disaster evolution.In the process of mine fire control,the pores and fissures in coal rock are well developed,the gas seepage and diffusion are strengthened,and the oxygen absorption characteristics of coal body are changed,thus affecting the spontaneous combustion characteristics of coal.Therefore,it is of great significance to study the thermal characteristics of coal oxidation under the action of heat flow for the prevention and control of coal spontaneous combustion.To study the heat transfer characteristics of coal oxidation,with different particle size of coal samples under different heating rate,with trace of heat meter for temperature programmed oxidation experiment.Under various operating conditions by analyzing the exothermic intensity as well as the changing law of activation energy of coal samples,to study the coal particle size and heating rate on the influence of coal spontaneous combustion oxidation characteristics,get different size exothermal intensity size order: 200-230 mesh >150-200 mesh > 80-150 mesh;Coal sample particle size as easy oxidation temperature,the faster the heating rate,oxidized spontaneous combustion of coal is enhanced.By means of thermostatic oxidation experiment,the variation trend of coal body temperature and gas product in different structure network under different temperature airflow was compared and analyzed.According to the research results,the oxidation capacity of each coal sample under the action of the same heat flow is as follows: fracture of coal> unloaded coal >o >the raw coal,under different temperature airflow,the higher the airflow temperature is,the stronger the coal oxidation ability is.The numerical software Fluent was used to simulate the variation rules of temperature field and velocity field under different working conditions.By comparing the flow field changes before and after the change,the influence of heat on the dynamic thermal balance of fractured coal body under different heat transfer surfaces and heat transfer paths was analyzed to reveal the microscopic mechanism of the oxidation and spontaneous combustion characteristics of fractured coal body and establish the seepage and heat transfer model of fractured coal body.