Experimental Study On Propagation Characteristics Of Methane Explosion With Different Concentrations In Columnar Space

With the rapid advancement of the country's industrial modernization,hydrocarbon-based flammable gases are commonly used as clean energy.Such major sources of danger frequently appear in the production,transportation,and storage processes.They often leak due to accidental or man-made causes,leading to burning.The explosion accidents,the number of accidents and economic losses have increased year by year,which seriously threatens the safety of material storage,transportation,and industrial production.The flames and pressure waves generated by the combustion and explosion are likely to damage nearby industrial installations and equipment,causing more serious security accidents.Therefore,this paper focuses on the mechanism and characteristics of methane explosion under different initial conditions,and provides important theoretical and technical support for the prevention and rescue of methane explosion accidents.In this thesis,theoretical analysis,numerical simulation and experimental research methods are used to systematically study the methane explosion propagation law in columnar space under different concentrations,different ignition positions and different initial pressures.According to the constant volume incendiary bomb explosion experimental device designed by North University of China,a numerical simulation model was established according to a ratio of 1:1.By setting different methane concentration conditions,the propagation law of methane explosion pressure at different concentrations was simulated.The results of the study found the following rules: the explosion pressure peak and explosion pressure peaks exhibit an inverse “V” quadratic function relationship with the change in methane concentration,and the explosion pressure peak and pressure rise rate peak at 9.5% equivalence ratio concentration.Based on theoretical analysis and numerical simulation of the propagation process of methane explosion,experiments were conducted using a constant-capacity combustion bomb explosion test device to study the propagation law of methane explosion in columnar space under different concentrations,different ignition positions and different initial pressure conditions.Changes in the analysis of experimental results lead to the following conclusions:(1)The concentration of methane has a significant impact on the propagation of methane explosions.The peak of explosion pressure and the rate of pressure rise are in an inverse “V” quadratic function relationship with the concentration of methane.The peak of explosion pressure reaches the maximum at 10.5%,and the peak value of pressure rise rate is the highest at 9.5% concentration.(2)Under the same initial pressure and methane concentration conditions,the closer the ignition position is to the center,the higher the methane explosion pressure rise rate and the greater the destructive force.(3)The peak value of methane explosion pressure and the peak value of pressure increase rate increase exponentially with the increase of initial pressure,showing a linear upward trend.As the initial pressure increases,the more energy is needed to ignite the methane/air mixture.(4)The methane explosion experiences three stages: the explosion pressure rising stage,the explosion pressure high value area,and the explosion pressure decay stage.During the pressure decay phase,the pressure sensor signal first drops to a negative value due to the pressure reflection wave,and then slowly returns to normal level.(5)By analyzing the comparison of numerical simulation results and experimental results,the feasibility and rationality of using FLUENT software to simulate the methane explosion process are verified,and the accuracy and reliability of the results of constant volume combustion incendiary explosion experiments are verified.