Ammonia combustion, owing to its zero greenhouse gas CO₂ emission, is attracting attention for energy utilization. However, the thermal radiation of NH₃ has not been reported and involved in the numerical simulations of ammonia flames, which may cause serious errors in estimating the laminar flame speeds. In this study, the effects of radiation reabsorption on the laminar flame speed at different equivalence ratios and elevated pressures were numerically investigated using planar NH₃/H₂/air flames. The Statistical Narrow-Band (SNB) model parameters for NH₃ were generated and used for simulations of NH₃/H₂/Air flames, considering the radiation reabsorption. It was found that the radiation reabsorption exhibited a non-monotonic behavior at ϕ = 0.65–1.6, with the maximum enhancement of flame speed up to 15.6%. The effects of radiation reabsorption were controlled by both radiation and chemistry. The preheat-induced chemical effect dominated at ϕ = 0.65–1.25 and the enhancement of flame speed was mainly influenced by H, OH and NH₂ radicals, which were primarily controlled by the reactions R36, R257 and R246, respectively. In contrast, the direct radiation effect dominated at ϕ = 1.25–1.6 and the enhancement of flame speed was mainly affected by the increasing mole fraction of NH₃. With increasing pressures, the preheat-induced chemical effect dominated at P = 1–10 atm and the enhancement of flame speed were mainly impacted by H and NNH radicals, which were controlled by the reactions R44 and R257, respectively. At higher pressures above 10 atm, direct radiation effect was dominating and the enhancement of flame speed was mainly controlled by the increasing optical thickness.

氨燃烧由于其零温室气体CO ₂排放而引起能源利用的关注。然而，NH ₃的热辐射尚未被报道和参与氨火焰的数值模拟，这可能会导致估计层流火焰速度的严重错误。在这项研究中，使用平面NH ₃ /H ₂ /空气火焰数值研究了辐射重吸收对不同当量比和升高压力下层流火焰速度的影响。生成NH ₃的统计窄带 (SNB) 模型参数并用于模拟 NH ₃ /H ₂/空气火焰，考虑到辐射重吸收。发现辐射重吸收在ϕ = 0.65-1.6 时表现出非单调行为，火焰速度的最大增强高达 15.6%。辐射重吸收的影响受辐射和化学控制。预热诱导的化学效应在ϕ = 0.65–1.25 时占主导地位，火焰速度的增强主要受 H、OH 和 NH ₂自由基的影响，分别主要受反应 R36、R257 和 R246 控制。相比之下，直接辐射效应在ϕ = 1.25 – 1.6 时占主导地位，火焰速度的增强主要受 NH ₃摩尔分数增加的影响. 随着压力的增加，预热诱导的化学效应在P =  1 - 10 atm 下占主导地位，火焰速度的提高主要受 H 和 NNH 自由基的影响，分别受反应 R44 和 R257 控制。在高于 10 个大气压的高压下，直接辐射效应占主导地位，火焰速度的增强主要受光学厚度增加的控制。