The Influence of the Obstacle Position on the Explosion Characteristics of Methane-Hydrogen-Air-Premixed Gas in a Closed 90 Bend Pipe

Experiment and numerical simulation are combined to reveal the influence of the obstacle position on the combustion and explosion characteristics of methane-hydrogen-air mixture in a closed 90 degrees bend pipe. The result shown that the synergistic effect of the obstacle and the hydrogen addition significantly enhances the explosion intensity of the mixed gas. Affected by the turbulent vortex near the obstacle, the flame is distorted significantly when it approaches the obstacles, thus enhancing the flame instability and accelerating the flame transition from layer to turbulence. The relative position between the obstacle and the elbow has an obvious influence on the excitation of flame propagation. When the distance between the obstacle and the elbow is more than 6 times the diameter of the pipe, the closer the obstacle is to the ignition end, the stronger the excitation effect. When the obstacle is located behind the elbow, the excitation effect of the obstacle on the flame propagation is weak. The maximum explosive overpressure in a 90 degrees bend is influenced by the coupling of obstacles and elbows. The research results can provide theoretical guidance for the safety and explosion protection of hydrogen transportation in industrial sites. The synergistic effect of the obstacle and the hydrogen addition significantly enhances the explosion intensity of the mixed gas. The relative position of obstacle and elbow in 90 degrees bend has obvious excitation effect on flame propagation and maximum explosion overpressure.image (c) 2024 WILEY-VCH GmbH