Experiment And Simulation Of Suppressing Methane Explosion With Heptafluoropropane/carbon Dioxide Mixed Gas And Ultrafine Water Mist

The explosion accident caused by gas leakage has always been an urgent problem in the coal mine field.Many scholars have also taken many corresponding measures,such as the use of gas concentration monitoring,drainage technology and ultra-fine water mist explosion suppression technology.In order to effectively improve the explosion suppression efficiency of ultrafine water mist,this paper builds a methane explosion suppression experiment platform by itself to conduct explosion suppression studies on carbon dioxide,heptafluoropropane,ultrafine water mist,heptafluoropropane/carbon dioxide mixed gas,and mixed gas with ultrafine water mist to explode.Overpressure,flame propagation speed,flame propagation structure and other parameters are used as analysis basis,and finally the heptafluoropropane/carbon dioxide mixed gas with ultrafine water mist synergistic explosion suppression mechanism is obtained,which has certain theoretical value and practical significance.In this paper,the heptafluoropropane/carbon dioxide mixed gas and the mutual cooperation mechanism between the mixed gas and the ultrafine water mist are studied respectively,and the coupling mechanism between the mixed gas and between the mixed gas and the ultrafine water mist is successively revealed.Promoting the development of methane explosion suppression technology provides scientific support.First,carbon dioxide,heptafluoropropane and ultra-fine water mist are used to individually suppress methane explosion experiments.the results showed that the inhibition of small amounts of carbon dioxide to methane explosion effect is very weak,only when the volume fraction is more than 12% show good inhibition effect;At the same volume fraction,the inhibition effect of heptafluoropropane on methane explosion is better than that of carbon dioxide.A small amount of ultrafine water mist can achieve a better inhibition effect,but with the increase of ultrafine water mist spray quantity,the improvement range of the anti-explosion effect of ultrafine water mist is gradually weakened.Then explosion suppression effect of heptafluoropropane/carbon dioxide mixed gas,and mixed gas with ultra-fine water mist,through the analysis of the explosion overpressure,flame propagation speed and flame propagation shape parameters change,such as discovery of heptafluoropropane and carbon dioxide mix proportion can affect the synergistic inhibition effect between the two,only when the heptafluoropropane volume fraction in the mixed gas is less than 40%,heptafluoropropane and carbon dioxide showed positive synergy.At the same time,when the heptafluoropropane/carbon dioxide mixed gas and the ultrafine water mist suppress the methane explosion together,the addition of the mixed gas can effectively enhance the suppression effect of the ultrafine water mist on the methane explosion.Finally,the numerical simulation and experimental results were mutually verified.Combining the flame temperature parameters in the simulation data and the explosion overpressure,flame propagation velocity and flame propagation structure in the experimental data,the coupling mechanism between heptafluoropropane/carbon dioxide mixed gas and the ultra-fine water mist was obtained.That is,when the mixed gas and ultrafine water mist inhibit methane explosion at the same time,the physical and chemical inhibition effect of the mixed gas can effectively reduce the explosion temperature at the initial stage of flame propagation,so that the ultra-fine water mist can stay in the pipeline for a longer time,and give full play to the physical inhibition effect of the ultra-fine water mist,so as to promote the detonation suppression effect of the ultra-fine water mist.