Abstract: Characteristics of impinging flame noise and pressure fluctuations with two opposed burners are studied based on opposed multi-burner(OMB) entrained-flow bench-scale gasifier. Analysis on spectrum of noise signal and pressure signal of impinging flame is made through Hilbert-Huang transform. The results show that medium and high frequency pressure fluctuations are mainly caused by complex combustion status in impinging flame zone and generates flame noise from 50Hz to 100Hz. The amplitude and waveform of jet flow flame noise are influenced by low frequency pressure fluctuations and reverse flow from impinging zone. Monitoring on acoustic signal of impinging flame which has a corresponding relationship with combustion status could be a flame diagnostic method in a gasifier.

摘要： 利用多喷嘴对置式气流床气化炉热模试验装置，对两喷嘴对置撞击火焰声学特性和压力波动进行了测量与实验研究，并通过Hilbert-Huang变换对火焰噪声信号及压力信号进行频谱分析。结果表明，气化炉内中高频压力波动主要由火焰撞击区内复杂的燃烧状况引发，并产生50~100 Hz频段的火焰噪声。射流火焰噪声受气化炉内低频压力波动影响，并且因来自撞击区的反向流的作用，火焰噪声的幅值和波形都会受到一定的影响。撞击区的火焰噪声信号与燃烧状况有一定的对应关系，可作为气化炉内火焰状况诊断的一种方式。

关键词: 声学, 撞击火焰, 火焰噪声, 压力波动, Hilbert-Huang变换