Study on the pressure characteristics and flame dynamics behavior of methane-hydrogen gas mixtures under the influence of multiple factors

In the context of the “dual-carbon” initiative, incorporating hydrogen into natural gas has emerged as a promising strategy for hydrogen energy utilization, drawing increasing attention from various industries. However, the associated risks of combustion and explosion warrant thorough investigation. This study systematically examines the pressure dynamics and flame behavior of methane–hydrogen mixtures in confined spaces under varying conditions. The results reveal a non-monotonic decay in outdoor overpressure during vented explosions. At high hydrogen doping ratios (80 %–100 %), the growth in peak overpressure diminishes, and the average flame propagation speed stabilizes. An increase in the venting coefficient reduces peak overpressure, delays explosion development, and decreases flame speed, with a critical range identified between 0.15 and 0.18 for 20 % hydrogen doping. Furthermore, within a side ratio range of 0.5–2.0 and under constant enclosure volume and height, the explosion overpressure peaks at a side ratio of 1.0, while deviations from this ratio lead to a reduced overpressure risk. These findings provide valuable insights into the explosion relief behavior of methane–hydrogen mixtures and offer essential guidance for the design of explosion mitigation systems and the development of risk management strategies.