Research On CH₄ Explosion Characteristics And CO₂ Explosion Suppression In Spherical Closed Device

Methane explosion is the most numerous in industry,and the consequences of explosion accidents are serious,it will lead to huge losses.Under general industrial production conditions,methane and carbon dioxide coexist frequently.For example,in areas where coal mines are dug and mined,when natural gas is mined and transported,it will explode if it leaks and comes into contact with open flames.Carbon dioxide can effectively prevent the secondary explosion and reduce pollution.Therefore,it is of great significance to study methane explosion and carbon dioxide explosion suppression.In this study,Fluent software is mainly used to establish models to calculate the methane explosion characteristics in spherical containers.The experiment was carried out in a 20L closed container,and the change law of explosion characteristics of CH₄/CO₂/Air mixed gas was discussed.The main results are as follows:（1）In the numerical simulation results,when the mixed gas of CH₄ and Air begins to explode,the explosion pressure at the center is 91.51Pa;The ignition temperature rises sharply from the initial 300K to 2165K;The flame speed is 1.18m/s;But when it touches the wall,it begins to fall and tends to be stable.CH₄concentration decreased from 0.058%to0.004%.The mass concentration of CH₄decreased from the initial 0.058%to 0%,and the mass concentration of O₂ decreased from the initial 0.219%to 0%.However,the mass concentrations of CO₂and H₂O increased from 0%to 0.153%and 0.124%respectively.（2）When the volume fraction of CH₄ is 10%,the explosion pressure is 727000Pa,and the fitting degree between experimental and simulated values is less than 7%.Therefore,the simulation can basically reflect the overall trend and the law of change.（3）The explosion pressure reached its peak when the methane concentration increased to 10%.At this time,the explosion pressure was 676000Pa,the pressure growth rate was25.3304Mpa/s,the maximum explosion intensity index K_G was 68.7573 MPa m/s,and the time for the explosion characteristic value to appear was about 0.17 s.（4）The CO₂ is added from 0%to 13%,the explosion suppression pressure and pressure rise rate are gradually decreasing.When the concentration of CO₂ is 0%,the explosion pressure is 0.6760Mpa and the pressure increase rate is 25.3304MPa/s;When the pressure increases to 13%,the pressure is 0.2626Mpa,the pressure growth rate is 2.5651Mpa/s,and the explosion strength index decreases from 68.7573 MPa m/s to 6.9628 MPa m/s.