Experimental Study On Secondary Explosion Of Gas Ignited By Gas Explosion In A Section Of Closed Pipeline

Gas explosion is one of the most common thermodynamic disasters in coal mine production in our country,which has a great threat to workers’ life safety and coal mining safety.After a gas explosion in a section of the tunnel,the explosion energy has the possibility to detonate the gas in the back section,which could lead multiple explosions.When there is a difference in gas concentration between the two sections,the ignition and detonation conditions are not the same.Moreover,the change in the distance between the gas in the front section and the gas in the back section,will also have an impact on the explosion consequences.In this paper,the method of combining theoretical analysis and experimental research is adopted to study the influence of different gas concentration distribution and secondary detonation distance on the secondary explosion characteristics of a section of gas explosion with an independent test device of gas secondary explosion ignited by gas explosion.The research work and main conclusions are as follows:The gas secondary explosion characteristics in the closed pipeline are studied when the concentration of gas in the front section is 8%,10%,12%,and the concentration of gas in the back section is 6%,8%,10%,12%,14%,which discover that when the gas concentration in the back section is constant,as the gas concentration in the front section is 10%,the peak pressure moment in each measuring point is the minimum,and the peak pressure is the maximum under a certain gas concentration in the back section.When the gas concentration in the back section is less than 8%,the value of peak pressure moment in the condition that the gas concentration in the front section is 12% in each measuring point is smaller than the value of peak pressure moment in the condition that the gas concentration in the front section is 8%,but it is opposite when the gas concentration in the back section is greater than 10%.When the gas concentration in the back section is less than 10%,the value of peak pressure in the condition that the gas concentration in the front section is 12% is bigger than the value of peak pressure in the condition that the gas concentration in the front section is 8%,but it is opposite when the concentration of gas in the back section is greater than 12%.When the gas concentration in the front section is constant,the peak value of explosion pressure increases first and then decreases,and the average flame velocity at the length-diameter ratio of 30.625 increases first and then decreases as the gas concentration in the back section increases,but the variation law of flame arrival time decreases first and then increases.Gas secondary explosion characteristics under different gas concentration distribution conditions are studied when the secondary detonation distances are 0,0.1m and 0.2m respectively,which discover that the peak pressure decreases,the peak pressure moment lengthens and the explosion intensity weakens with the increase of the secondary detonation distance when the concentration in each section is lower than 10% for the low gas concentration distribution,but the peak pressure increases,the peak pressure moment is shortened,and the explosion intensity increases for high gas concentration distribution with the gas concentration greater than 12%.The flame arrival time increases with the increase of propagation distance,and the flame arrival time difference between different working conditions near the end of the pipeline is the largest.As the gas concentration in the front section is 8% and 10% and the gas concentration in the back section is lower than 10%,the average flame velocity at 30.625 decreases with the increase of the secondary detonation distance,but when the gas concentration in the back section is higher than 12%,the average flame velocity fluctuates with the increase of the secondary detonation distance.When the gas concentration in the front section is 12%,the average flame velocity at the aspect ratio of 30.625 increases with the increase of the secondary detonation distance.The research results enrich the law of secondary gas explosion disaster caused by gas explosion in a section of coal mine roadway,and provide theoretical support for the research and development of prevention and control technology of secondary gas explosion induced by gas explosion in coal mine roadway.Figure [46] table [17] reference [90]...