Pressure Rise Effect of Hydrogen-Methane Mixture Combustion under Dual Heterogeneous Obstacles

The disaster characteristics of gas combustion and explosion are hot and key topics in domestic and international research. Studying the combustion and explosion characteristics under complex constraint conditions is of great significance. Regarding rigid and flexible obstacles, the combustion and explosion process of hydrogen-doped methane gas in a long straight pipeline with double heterogeneous obstacles was explored through experiments. The results show that, compared with the obstacle-free environment, the influence of double obstacles on the flame speed, explosion pressure, and explosion intensity index increases with the increase in the blockage ratio of the flexible obstacle and the addition of hydrogen. Moreover, the increase in explosion pressure and explosion intensity index is greater than that of the flame speed. Under the combined action of hydrogen addition and double obstacles, the flame contact speed can increase by up to 176.51%, and the maximum speed can increase by up to 316.40%. The double obstacles cause the pressure in the upstream region to rise first and then fall, and the pressure oscillation in the downstream region is obvious. After hydrogen addition, compared with the obstacle-free environment, the maximum explosion pressure in the pipeline can increase by up to 1280.9%, and the maximum explosion intensity index can increase to 167.65 times. In the layout engineering projects of constraint facilities, flexible obstacles with a smaller blockage ratio should be preferred to effectively mitigate the consequences of explosion hazards.