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针对钝体火焰稳定器结构的模型预混燃烧室的燃烧不稳定性现象进行了实验研究和数值模拟.实验中利用动态压力传感器测量了不同当量比时燃烧室内动态压力的频率和振幅.结果表明:随当量比增加,不稳定性频率从251Hz增加到258Hz.不稳定性振幅与大气压力比值从2.7%增加到6.1%.对燃烧室进行了定常和非定常数值模拟以及声学模态分析,得到了周期性旋涡脱落的频率为260Hz和燃烧室系统的前5阶本征声学模态频率.其中第3阶纵向声学模态频率与实验值基本一致,说明维持不稳定性的机理为钝体火焰稳定器后旋涡的周期性对称脱落和燃烧室系统的第3阶纵向声学模态形成了耦合.
Aiming at the combustion instability phenomenon of the model premixed combustor with blunt body flame stabilizer, the dynamic pressure sensor was used to measure the dynamic pressure in the combustion chamber with different equivalence ratios.The results show that : As the equivalence ratio increases, the instability frequency increases from 251Hz to 258Hz, and the ratio of instability amplitude to atmospheric pressure increases from 2.7% to 6.1%. The steady and unsteady numerical simulation of the combustion chamber and acoustic modal analysis The frequency of periodic vortex shedding is 260Hz and the first 5 order intrinsic acoustic modal frequencies of the combustion chamber system, of which the third order longitudinal acoustic modal frequency is basically consistent with the experimental value, indicating that the mechanism of maintaining instability is a bluff body flame The periodic symmetrical shedding of the stabilizer vortex forms a coupling with the 3rd longitudinal acoustic mode of the combustor system.