Effect of unilateral obstacles and hydrogen blending on the explosion suppression performance of copper foam for methane/hydrogen mixtures

To explore the effect of unilateral obstacles and hydrogen blending on the explosion suppression effect of copper foam, the changes in characteristic parameters, such as flame structure evolution, overpressure waveform, and peak, were analyzed. The results show that increasing the hydrogen doping ratio accelerates obstacle-induced flame stretching, bending, and vortex-driven propagation. The combined presence of unilateral obstacles and hydrogen significantly raises the probability of quenching failure caused by flame penetration through the copper foam: quenching failure only at 30% hydrogen doping ratio with a single obstacle, penetration at ≥ 20% with double obstacles, and ≥ 10% with multiple obstacles. At high hydrogen doping ratios, the velocity peak decreases with obstacle number, revealing that an optimal obstacle density is dominated by heat loss and spatial constraints beyond that. Increasing both the hydrogen blending ratio and obstacle number doubles the overpressure peak. Copper foam significantly mitigates abrupt upstream overpressure changes and limits downstream overpressure increase to within one time, a pressure buffer. These findings support safer hydrogen-enriched methane networks.