Pressurized oxy-fuel combustion is regarded as a new generation of oxy-fuel technology. The ignition delay times of methane in an O₂/N₂ atmosphere (0.21O₂ + 0.79N₂) and an O₂/CO₂ atmosphere (0.21O₂ + 0.79CO₂) were measured in a shock tube at a pressure of 0.8 atm, an equivalence ratio of 0.5, and within a temperature range of 1501–1847 K. The present experimental data and the experimental data of Hargis and Peterson at 1.75 and 10 atm were adopted to evaluate five representative chemical kinetic models. This paper studied the chemical effects (chaperon effects of CO₂ and the effects of reactions containing CO₂) and physical effects of CO₂ on the ignition of methane at different pressures and temperatures in detail using a modified model. Artificial materials X and Y were employed to analyze the chemical and physical effects. The analysis showed that the physical effects of CO₂ inhibit the ignition of methane and are not sensitive to the temperature. The chemical effects of CO₂ vary greatly with the pressure and temperature. At 0.8 and 1.75 atm, the chemical effects of CO₂ promote the ignition of methane at a high temperature while suppress the ignition of methane at a low temperature. The chaperon effects of CO₂ promote the ignition of methane in O₂/CO₂ atmospheres at a high temperature mainly because of HCO + M ⇔ CO + H + M. The chaperon effects of CO₂ suppress the ignition of methane at a low temperature because of 2CH₃ (+M) ⇔ C₂H₆ (+M). The chemical effects of CO₂ offset half of the physical effects of CO₂ at a high temperature, and those two effects are great at a low temperature, which is the reason for the fact that the effect of CO₂ is subtle at a high temperature and evident at a low temperature. At 10 atm, the chemical effects of CO₂ suppress the ignition of methane at 1350–1700 K. The chaperon effects of CO₂ suppress the ignition of methane mainly as a result of 2CH₃ (+M) ⇔ C₂H₆ (+M) and are strengthened with the decrease of the temperature. The inhibition of reactions involving CO₂ is mainly attributed to CO + OH ⇔ CO₂ + H and weakened with the decrease of the temperature; thus, the chemical effects of CO₂ on the ignition are almost not sensitive to the temperature. The effects of CO₂ have almost not change with the temperature at 10 atm.

中文翻译：

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不同压力和温度下CO ₂对甲烷点火延迟时间影响的实验和数值研究

加压的含氧燃料燃烧被认为是新一代的含氧燃料技术。在冲击管中，在O ₂ / N ₂气氛（0.21O ₂ + 0.79N ₂）和O ₂ / CO ₂气氛（0.21O ₂ + 0.79CO ₂）中测量甲烷的点火延迟时间。 0.8 atm，当量比为0.5，且在1501-1847 K的温度范围内。采用当前的实验数据以及Hargis和Peterson在1.75和10 atm的实验数据来评估五个代表性的化学动力学模型。本文研究了化学效应（CO _2的分子伴侣效应）和含CO的反应的效果₂）和CO的物理效应₂使用修改模型上甲烷中的详细不同的压力和温度下的点火。人工材料X和Y用于分析化学和物理作用。分析表明，CO ₂的物理作用抑制了甲烷的点火，并且对温度不敏感。CO ₂的化学作用随压力和温度而变化很大。在0.8和1.75 atm时，CO ₂的化学作用促进高温下甲烷的着火，同时抑制低温下甲烷的着火。CO ₂的分子伴侣效应促进甲烷的点火为O ₂ / CO ₂气氛在高温下，因为HCO + M⇔CO + H + M的主要是CO的伴侣作用₂抑制甲烷中的，因为2CH的低温点火₃（+ M）⇔C ₂ H ₆（+ M）。CO ₂的化学作用抵消了高温下CO ₂的物理作用的一半，而这两种作用在低温下都很大，这就是在高温下CO ₂的作用微妙的原因。并且在低温下很明显。在10个大气压下，CO ₂的化学作用抑制甲烷的点火在1350至1700年的CO K.的伴侣作用₂抑制甲烷的点火主要作为2CH的结果₃（+ M）⇔Ç ₂ ħ ₆（+ M），并用的降低得到加强温度。涉及CO ₂的反应的抑制作用主要归因于CO + OH⇔CO ₂ + H，并且随着温度的降低而减弱。因此，CO ₂对点火的化学作用几乎对温度不敏感。在10 atm的温度下，CO ₂的作用几乎没有变化。