Explosion suppression technology plays a vital role in reducing the hazardous effect of gas explosion incidents. This study aimed to investigate the explosion suppression effect of two-phase composite inhibitor mixtures of hexafluoropropane and dry water modified by potassium carbonate. The explosion pressure and time parameters of methane-air mixtures were obtained experimentally. Then the synergistic mechanisms on methane explosion suppression was analyzed theoretically. Results of the experiments shows that the combustion time of methane-air mixtures increase with the rising ratio of dry water modified by potassium carbonate in the coupled inhibitors. Dry water modified by potassium carbonate greatly enhanced the explosion suppression effect of C₃H₂F₆. The critical inhibition ratios of gas-solid inhibitors are 5%-6 g, 3%-6 g, and 1%-4 g for fuel-lean, stoichiometric, and fuel-rich methane-air mixtures, respectively. Moreover, the physical inhibition effects of the dilution in the premixed mixtures and the reduction in the flame temperature, as well as the chemical suppression effect, synergistically inhibit the deflagration of methane-air mixtures. In terms of the chemical inhibition, it is KCO₃, KOH, OH and fluorine-containing groups that produced by the pyrolysis of potassium carbonate and C₃H₂F₆ reduce the concentration of key radicals of methane explosion. The results of the work will help to providing the theoretical basis for the development of more effective explosion-suppressant and promoting the related explosion-suppressing technology.

A novel prefabricated wall panel structure for substations was developed by integrating fiber cement board, aluminum honeycomb plate, and aluminum alloy plate. The dynamic response characteristics of the structure under explosive loads were investigated through experimental studies. The effects of overpressure loads at different explosive mass and loading distances were examined, and the impact of varying honeycomb cell sizes on structural deformation failure mode, back face deflection and strain, core compression, and fiber cement board crack distribution was analyzed. The results indicate that within a confined space, the time characteristics of explosion overpressure are similar to those in an unconfined space. The peak overpressure measured independently at the center is between 2.4 and 10.0 times that measured directly at the edge. The positive pressure duration measured independently at the center is between 0.44 and 0.71 times that measured directly at the edge. The predominant deformation mode of the structure involves front panel depression and rear panel bulging. Horizontal cracks in the front face of the fiber cement board are predominantly located near its long side boundary, while cracks in the back face are mainly distributed near its center and diagonal areas. Compared with structures featuring smaller honeycomb cell sizes, those with larger honeycomb cell sizes exhibit greater residual deflection on their back faces and longer total crack lengths in their fiber cement boards.