甲烷/空气典型混合模式在约束空间内的燃烧特性研究

燃料质量浓度分布在一定程度上影响混合气体的燃烧效率，能使燃气充分混合的同轴射流、旋片同轴、轴切结合、切向旋流等典型混合模式在航空发动机、燃气轮机及火箭发动机等先进燃烧技术应用中较为常见。因此，设计了甲烷/空气部分预混的燃烧实验装置，较为系统地实验研究了旋流数和轴向流速对混合气体在约束空间燃烧室内燃烧特性的影响。结果表明：对于有中心射流的混合结构，燃气轴向流速较低时产生黄色火焰，增大轴向流速，黄色火焰转为蓝色湍流火焰，且温度分布趋于均匀；纯切向旋流燃烧器的掺混效果较好，受燃气轴向流速的影响小，火焰结构稳定，均为蓝色火焰，温度轴/径向分布均匀且趋势一致，同当量比下燃烧产物中的污染物体积分数最小。

Research on Combustion Characteristics of Typical Methane/Air Mixing Patterns in Confined Spaces

The fuel concentration distribution affects the combustion efficiency of the gas mixture to a certain extent.Typical mixing modes such as coaxial jet,coaxial vane,axial tangential combination and tangential swirl are more common in advanced combustion technology applications such as aero engines,gas turbines and rocket engines.Therefore,a combustion experimental setup with partial premixing of methane/air is designed,and the effects of the swirling number and axial flow rate on the combustion characteristics of the gas mixture in the confined space of combustion chamber are studied experimentally in a more systematic way.The results show that for the mixing structure with central jet,yellow flame with large amount of carbon smoke is produced when the axial flow rate of gas is low,and the yellow flame turns into blue turbulent flame when the axial flow rate is increased,and the temperature distribution tends to be uniform; while the mixing effect of pure tangential swirl burner is better,the influence of the axial flow rate of gas is small,the flame structure is stable with blue flame,and the temperature is uniformly distributed in the axial and radial directions with the same trend.The volume fraction of pollutants in the combustion products is the smallest at the same equivalent ratio.