降低冒烟数燃烧室火焰筒头部改进设计研究

为了解决某型航空发动机燃烧室冒烟数较大的问题,通过分析航空煤油的燃烧化学反应过程和燃烧室内油气掺混燃烧过程,确认了炭烟的产生主要发生在初级反应阶段火焰筒的头部区域。因此提出改进措施,将火焰筒头部的单级旋流器更换为旋流杯,并对旋流杯的结构参数进行调整。采用数值模拟及扇形试验对改进前后的火焰筒性能进行对比分析。研究表明：相对于单级旋流器,旋流杯使燃烧室头部流场由单涡结构变为双涡结构,燃油分布更加均匀,在头部高温的环境中降低了局部富油程度,从而减少了头部炭烟的生成;改进后,燃烧室冒烟数大幅降低,总压恢复系数变化不大,贫油熄火油气比达到了0.004 6,能够满足发动机使用要求。

Investigation on Design Improvement of Combustor Dome for Reduction of Smoke Number

To solve the problem of relatively large smoke number for an aero engine combustor,the determination of the soot formation mainly occurring in the flame tube dome during the stage of primary reaction is made by analysis of the processes for combustion chemical reaction of the aviation kerosene and oil air mixing combustion in combustor.The improvement measure is proposed to replace the single stage swirler of the flame tube dome with the swirler cup and adjust its structural parameters.The comparative analysis is carried out for the performance of the flame tube before and after its improvement through the numerical simulation and the sector test.The research results show that the flow field of combustor dome is changed from single vortex to double vortexes and the fuel distribution is more uniform by application of the swirler cup compared with the single stage swirler.The degree of the local fuel rich is reduced in the high temperature of the dome,thus the soot formation is decreased.Through the design improvement,the smoke number of combustor is reduced largely,the total pressure recovery coefficient doesn''t have great change and the lean flameout oil air ratio reaches 0.004 6.It can still satisfy the requirements for the engine opeation.