Abstract: An innovative N2 injection technology in which N2 is injected into the air stream from the middle of flame tubes，was proposed during the process of developing high-performance syngas turbine combustors. It is designed to mitigate the problems of disordered air flow rate distribution and flame instability caused by the design that N2 is injected from the head of flame tubes. At first，an evaluation between the two designs was carried out based on the results of 3-D computational fluid dynamics (CFD) and chemical reactor networks (CRN). Then，the new design was further studied both numerically and experimentally. The results indicate that this innovative N2 injection design would not only meet the low NO_x emission standard (<25ppmvd@15%O₂) but also effectively fix the distorted air flow rate distribution problem，hence increases the flame stability. Moreover，the results show that this design allows a further increment of N2 injection quantity. Therefore it has a potential to achieve an ultra-low NO_x emission(10ppmvd@15%O₂).

Key words: Gas turbine；Syngas；Combustor；Numerical simulation

摘要： 以开发高性能燃气轮机合成气燃烧室技术为背景，针对从火焰筒头部喷射N2降低NO_x引起空气分配畸变、影响燃烧稳定的问题，提出了从火焰筒中部喷射N2的中间稀释方案。利用三维数值模拟和化学反应网络模型(CRN)方法对两种方案进行了比较，随后对中间稀释方案进行了更深入的数值研究，并进行了实验验证。结果表明:中间稀释方案能够在降低NO_x排放(<25ppmvd@15%O₂)的同时有效缓解头部空气分配畸变的问题，增强了燃烧稳定性，并使进一步增加N2喷射量、实现更低NO_x排放(10ppmvd@15%O₂)成为可能。

关键词: 燃气轮机；合成气；燃烧室；数值模拟