低旋流燃烧的火焰稳定机理研究

Low swirl combustion（LSC）which is one of the lean-premixed combustion technologies, has characteristics of higher combustion efficiency, good combustion stability, low temperature flame region and emissions of ultra-low NOx. LSC is one promising solution to resolve low emissions and long life issues of aero engine combustors. Currently, the most published literature corresponding to LSC focus on the gaseous fuel. If LSC is applied to aero engine combustor, it is inevitable to use liquid kerosene. Fuel atomization and evaporation processes, as well as the mixing process, play key roles in controlling combustion characteristics such as flame stability, combustion efficiency and pollutant emissions. The primary objective of this work is to develop optical diagnostic techniques and large eddy simulation methods and to investigate the combustion dynamics of a commonly used low-swirl burner with kerosene. Details of instantaneous flame structures and temperature, species on low swirl combustion will be studied in this work. Then, performance parameters about LSC such as lean bowoff equivalence ratio, combustion efficiency, and emissions can be evaluated to access the feasibility of adapting low-swirl burners to liquid fueled gas turbines. This will be necessary to understand the flame stability mechanism and to provide basic information for optimizing the low swirl combustion system.

低旋流燃烧是一种贫油预混燃烧技术,其燃烧效率高、火焰稳定性强、燃烧区域温度低、NOx排放超低，可能是未来航空发动机实现长寿命低污染排放的解决方案之一。国内外对低旋流燃烧技术的研究主要集中在气态燃料方面，如将低旋流燃烧技术应用于航空发动机不可避免地要采用液态煤油为燃料，那么燃料的雾化、蒸发将对发动机的燃烧特性如火焰稳定性、燃烧效率、污染物排放、出口温度分布等有重要影响。本项目拟针对低旋流燃烧中的火焰稳定问题，应用非定常光学测量方式，结合大涡数值模拟方法和FGM湍流燃烧模型，研究低旋流数流场中的组分和温度分布，分析主燃区的火焰结构演化进程，揭示低旋流燃烧的火焰稳定机理，确定低旋流燃烧器的贫油熄火油气比、燃烧效率、污染排放指数，探索低旋流燃烧工程实用性，支撑低排放燃烧室的技术发展。

低旋流燃烧是一种贫油预混燃烧技术,其燃烧效率高、火焰稳定性强、燃烧区域温度低、NOx排放超低，可能是未来航空发动机实现长寿命低污染排放的解决方案之一。国内外对低旋流燃烧技术的研究主要集中在气态燃料方面，对液态燃料，雾化、蒸发将和混合过程一样对燃烧特性如火焰形状、稳定性、污染物排放有重要影响。本项目开展了碳氢燃料的低旋流燃烧技术研究，首先，采用非定常光学测量方式对关键燃烧区的速度、温度分布等进行精细测量，给出燃料在流动过程中的燃烧反应进行程度及火焰结构演化过程，并结合大涡模拟方法揭示低旋流燃烧的火焰稳定机理;其次，分析低旋流燃烧室的性能如贫油熄火油气比、燃烧效率、污染物排放指数，探索了低旋流燃烧用于航空发动机的可行性，支撑低排放燃烧室的技术发展。