LAUSR

An in-depth study of the combustion characteristics and mechanism of methane hydrate is necessary for its safe storage and transportation and for providing high efficiency in combustion applications. To investigate the mechanistic action of water on the combustion characteristics, a combustion experiment with a methane hydrate sphere was carried out. The action law of the physical state of water on the flame was qualitatively investigated, and the methane to water vapor mass ratio and the rate of gas release during combustion were quantitatively determined. In addition, a chemical dynamics simulation was carried out using a hedging flame model in CHEMKIN software. The influencing mechanism of water vapor on the combustion flame characteristics was analyzed. Combustion experiments revealed that the methane hydrate sphere exhibits good flame morphological stability during the fierce combustion phase. The accumulation of a water film promotes methane bubbles and accelerates the evaporation of water during the unstable combustion phase, leading to flame instability. The self-protection effect significantly influenced the gas release rate, thereby affecting the flame characteristics. The simulation results revealed that, on the one hand, the addition of water vapor significantly changed the reaction process of some elementary reactions (chemical effect), which led to a decrease in flame temperature. On the other hand, the concentration of the intermediate element components was also decreased (physical effect), exhibiting an inhibitory effect on the combustion rate.