The methane oxy-fuel combustion highly diluted by CO₂ at supercritical region has the best potential for its near-zero emission characteristics and high thermal efficiency, while its auto-ignition characteristic is still not clear. In current investigation, a model with detailed chemical kinetic mechanism was introduced to research its ignition delay times (IDs). Results showed that the fold points in low-temperature and high-pressure region is due to CH₃O₂ which only involved in Aramco-Mech 1.3. When temperature increases, the inhibition of the termination reactions plays a dominate role at low pressure, while the promotion of the branching reactions contributes more to the acceleration of ignition at high pressure. Five dominant pathways and their variations were clarified to depict the inhibition effect of the ratio of CO₂/O_2. Based on the newly proposed combustion mode, it was found that temperature dependence of the nonnegligible CO₂ collision effect is opposite under low and high pressure with full-oxy combustion mode. This investigation extended the research region to higher pressure and comprehensively studied the relevant factors on the auto-ignition which not only provides theoretical reference for the chemical kinetics study of methane, but also contributes to the further researches of EGR, SCF and near-zero emissions technologies.

在超临界区被CO ₂高度稀释的甲烷氧燃料燃烧具有近乎零排放特性和高热效率的最佳潜力，而其自燃特性仍不清楚。在目前的研究中，引入了具有详细化学动力学机理的模型来研究其点火延迟时间（ID）。结果表明，低温高压区的折点归因于CH ₃ O _2。仅涉及Aramco-Mech 1.3。当温度升高时，在低压下终止反应的抑制起主要作用，而支化反应的促进则在高压下加速点火。阐明了五个主要途径及其变化，以描述CO ₂ / O ₂比的抑制作用_。基于新提出的燃烧模式，发现了不可忽略的CO _2的温度依赖性。在全氧燃烧模式下，低压和高压下的碰撞效果相反。该研究将研究范围扩大到更高的压力，并综合研究了自燃的相关因素，这不仅为甲烷的化学动力学研究提供了理论参考，而且为进一步研究EGR，SCF和接近零排放做出了贡献。技术。