基于声学特征信号提取的燃烧不稳定性试验研究

Experimental research on combustion instability based on acoustic characteristic signal extraction

为研究航空发动机燃烧不稳定时的声学特征,对发动机燃烧室进行了燃烧不稳定状态下的声学测试试验。测试结果表明,燃烧不稳定现象发生时会伴随着明显的离散单音声学特征信号出现。采用特征频率信号加强的奇异值分解法对离散单音声学特征信号进行提取及分析,得出该型发动机燃烧室不稳定燃烧时的声源位置位于火焰筒内的火焰区域,声波传播为纵向传播,声模态为一阶纵向模态。可为今后航空发动机燃烧不稳定性研究提供参考。

To study the acoustic characteristics of combustion instability in the aero-engine,an acoustic test was carried out on a certain combustor under combustion instability.The test results show that when combustion instability occurs,it is accompanied by the emergence of obvious discrete acoustic characteris tic signals.Discrete acoustic characteristic signals were extracted and analyzed by using characteristic fre quency signal enhancement combined with Singular Value Decomposition(SVD)methods,deducing that the sound source was located at the flame area in the liner,sound wave propagation was longitudinal and sound mode was the first-order longitudinal,which can be referential for future research on combustion in stability of aero-engine.