Study On The Influence Of Inert Gas In Square Pipe On Propane Explosion Characteristics

Clean energy has been widely used due to its advantages of renewable and less pollution.Propane,as a kind of clean energy,fire and explosion accidents occurs frequently in the process of its use,resulting in huge property losses and casualties,has a great risk.Based on the practical background,the self-designed square visualization pipeline system and combines high-speed photography/schlieren technique were used to compare and study the effects of carbon dioxide,nitrogen and argon on propane-air explosion characteristics.The results were as follows:(1)The explosion limit range and equivalent concentration values of propane were determined by using square visualization pipe test: 2.25%~10.25%,4.5%,at room temperature.(2)Using the square visualization pipeline,the effects of the change of the integral number of carbon dioxide,nitrogen and argon in the equivalent propane-air premixed gas on the explosion pressure of the premixed gas were tested.The results showed that the maximum explosion pressure decreases with the increase of the number of carbon dioxide,nitrogen and argon gas in the premixed gas.When adding the same volume fraction of carbon dioxide,nitrogen and argon to the premixed gas,the effect on the maximum explosion pressure of the premixed gas was ordered from large to small: carbon dioxide > nitrogen > argon.(3)The structure change of the equivalent propane-air premixed gas explosion flame during propagation and the influence of different volume fraction of inert gas on the premixed gas flame structure were studied by high speed/grain pattern technique.The result showed that: when no inert gas was added,the premixed gas flame gradually changes from the "ball" shape at the initial stage of ignition to the "fingertip" shape,and finally forms a "tulip" shaped flame.When the number of carbon dioxide,nitrogen and argon gas in the premixed gas increased gradually,the instability of the flame during the propagation process was gradually aggravated,and the structure was seriously deformed.Moreover,the time when the flame changes from the "ball" shape to the "fingertip" shape and the formation time of the "tulip" flame appear to lag;when the integral numbers of carbon dioxide,nitrogen,and argon gas were increased to 18%,21%,and 24%,respectively,the premixed gas flame did not form a "tulip"-shaped flame during propagation.(4)The effect of the change of the volume fraction of inert gas in the premixed gas on the propagation velocity of the equivalent propane-air premixed gas explosion flame was studied.The results showed that with the increase of the number of carbon dioxide,nitrogen and argon gas,the maximum velocity and average velocity of premixed gas flame propagation decrease.When the integral numbers of carbon dioxide,nitrogen,and argon gas reached 30%,33%,and 39%,respectively,the premixed gas explosion was completely suppressed.