多孔燃烧器中氨/空气燃烧特性数值研究

氨具有氢密度高、生产成本低、基础设施完善等优点,作为一种潜在的可再生替代燃料受到了广泛的关注。目前,仅有少数研究关注氨气燃烧喷嘴的研究,针对氨气稳定燃烧喷嘴的研究尤其不足。为实现氨燃料的稳定燃烧和低污染物排放,本研究提出了一种氨用多孔介质燃烧器。对氨用多孔介质燃烧器建立了二维数值模型,并对预混氨/空气在多孔介质燃烧器中的燃烧性能进行了评价,考察了不同进口速度u₀、当量比Φ和多孔介质导热系数对氨/空气火焰特性和NO排放的影响。结果表明,多孔介质燃烧器能在u₀ = 3 ~ 7 m/s和Φ = 0.9 ~ 1.2条件下稳定燃烧;随着多孔介质导热系数的增大,火焰最高温度下降且火焰位置向上游移动;减小进口速度和增大当量比能够显著降低NO的排放。

Numerical Study on Ammonia/Air Combustion Characteristics in a Porous Burner

Ammonia has the advantages of high hydrogen density, low cost, and complete infrastructure, making it a potential renewable alternative fuel that has received extensive attention. At present, there are only a few studies focusing on the research of ammonia combustion nozzles, and the research on ammonia stable combustion nozzles is particularly insufficient. In order to achieve stable combustion of ammonia fuel and low pollutant emissions, a porous medium burner for ammonia was proposed in this study. A two-dimensional numerical model was established for a porous medium burner for ammonia, and the combustion performance of premixed ammonia/air in a porous medium burner was evaluated. The effects of different inlet velocities, equivalent ratios and thermal conductivity of porous media on ammonia/air flame characteristics and NO emissions were investigated. The results showed that the porous medium burner can stably burn at inlet velocity (u₀) of 3-7 m/s and equivalent ratio (Φ) of 0.9-1.2. As the thermal conductivity of the porous medium increased, the maximum flame temperature decreased and the flame position moved upstream. Reducing the inlet velocity and increasing the equivalence ratio can significantly reduce NO emissions.