The Adiabatic Flame Temperature (AFT) in combustion represents the maximum attainable temperature at which the chemical energy in the reactant fuel is converted into sensible heat in combustion products without heat loss. AFT depends on the fuel, oxidizer, and chemical composition of the products. Computing AFT requires solving either a nonlinear equation or a larger minimization problem. This study obtained the AFTs for oxy-methane (methane and oxygen), oxy-hydrogen (hydrogen and oxygen), air-methane (methane and air), and air-hydrogen (hydrogen and air) for stoichiometric conditions. The reactant temperature was 298.15 K (25{\deg}C), and the pressure was kept constant at 1 atm. Two reaction mechanisms were attempted: a global single-step irreversible reaction for complete combustion and the GRI-Mech 3.0 elementary mechanism (53 species, 325 steps) for chemical equilibrium with its associated thermodynamic data. NASA CEARUN was the main modeling tool used. Two other tools were used for benchmarking: an Excel and a Cantera-Python implementation of GRI-Mech 3.0. The results showed that the AFTs for oxy-methane were 5,166.47 K (complete combustion) and 3,050.12 K (chemical equilibrium), and dropped to 2,326.35 K and 2,224.25 K for air-methane, respectively. The AFTs for oxy-hydrogen were 4,930.56 K (complete combustion) and 3,074.51 K (chemical equilibrium), and dropped to 2,520.33 K and 2,378.62 K for air-hydrogen, respectively. For eight combustion modeling cases, the relative deviation between the AFTs predicted by CEARUN and GRI-Mech 3.0 ranged from 0.064% to 3.503%.

翻译：燃烧中的绝热火焰温度（AFT）表示在无热损失条件下，反应物燃料中的化学能转化为燃烧产物显热时所能达到的最高温度。AFT取决于燃料、氧化剂及产物的化学组成。计算AFT需要求解非线性方程或更大规模的极小化问题。本研究获得了化学计量条件下氧-甲烷（甲烷与氧气）、氧-氢（氢气与氧气）、空气-甲烷（甲烷与空气）及空气-氢（氢气与空气）的AFT。反应物温度为298.15 K（25°C），压力恒定为1 atm。研究尝试了两种反应机理：用于完全燃烧的全局单步不可逆反应，以及用于化学平衡的GRI-Mech 3.0基元反应机理（53种组分，325步反应）及其相关热力学数据。NASA CEARUN是主要建模工具，另使用两种工具进行基准验证：基于GRI-Mech 3.0的Excel实现与Cantera-Python实现。结果表明：氧-甲烷的AFT分别为5,166.47 K（完全燃烧）与3,050.12 K（化学平衡），空气-甲烷的AFT则分别降至2,326.35 K与2,224.25 K；氧-氢的AFT分别为4,930.56 K（完全燃烧）与3,074.51 K（化学平衡），空气-氢的AFT分别降至2,520.33 K与2,378.62 K。在八种燃烧建模案例中，CEARUN与GRI-Mech 3.0预测的AFT相对偏差范围为0.064%至3.503%。