Electrical fires caused by cable degradation constitute a critical ignition source for gas and dust explosions in underground mining environments, where aged cable insulation serves as the primary contributing factor. Under harsh mining conditions, characterized by elevated ambient temperatures and high operating voltages, electrical cables experience accelerated electrothermal aging due to synergistic temperature-voltage degradation mechanisms. However, existing studies have primarily concentrated on investigating the influence of individual stress factors on cable fire behavior. To address this research gap, this study developed an electro-thermal synergistic aging platform and conducted comparative investigations of flame propagation characteristics and thermal stability for two different-sized polyethylene(PE) wires using flame spread tests and simultaneous thermal analysis(TG-DSC), under both electro-thermal synergistic aging and pure thermal aging conditions. The results demonstrate that electro-thermal synergistic aging, compared to thermal aging alone, reduces the flame spread rate and mass loss rate to 91% and 71%, respectively, while significantly increasing molten dripping frequency. Furthermore, the insulation layer exhibits an earlier melting peak, a delayed decomposition peak, and more substantial increases in residual carbon content. These findings elucidate the synergistic effects of electrical and thermal stresses on the combustion and pyrolysis behavior of PE wire, offering valuable theoretical insights for fire risk assessment and prevention in underground mining electrical systems.

Feed and its additive dusts have a high combustion heat, which poses significant risks of dust explosions during production, thereby threatening life and property safety. Currently, premix inhibitors are widely used as explosion suppression measures. However, traditional inhibitors are inedible and cannot be added to feed dust to achieve explosion suppression. Therefore, this study focuses on the dust of DL-methionine(DLM), a primary additive in feed, and investigates the effect of self-synthesized phytic acid-cytosine(PA-CY), an edible biomass-based compound with nutritional value and environmental friendliness, on the flame propagation characteristics of DLM dust explosions. The flame propagation process was recorded through high-speed photography and visualized in a vertical pipe while calculating the flame velocity. Additionally, thermocouples were used to monitor changes in flame temperature. The results indicate that as the mass fraction of PA-CY increases, the luminosity of DLM dust explosion flames consistently decreases, severely disrupting the flame structure. After adding 20% PA-CY, there is a reduction of 50.0%, 52.2%, and 46.7% in peak velocity(from 27.66 m/s to 13.83 m/s), average velocity(from 14.39 m/s to 6.88 m/s), and peak temperature(from 1014℃ to 540℃) respectively. Moreover, when the mass fraction of PA-CY reaches 30%, ignition of the dust cannot occur indicating significant inhibitory effects provided by PA-CY.