自激脉动燃烧器脉动频率跳变的实验研究

对自激脉动燃烧器脉动频率的跳变现象进行实验研究，测得了此类燃烧器频率随功率、当量比跳变的规律：当燃烧器功率降低到某一临界值时，其工作频率将从基波型的频率值上跳到高一次的谐波型的频率值；进一步降低燃烧器的功率，其工作频率将在这一谐波振型上按声学规律继续下降，反之亦然；当量比较高时，燃烧器在功率较高的情况下就会出现频率跳变；当量比过低时，会导致燃烧器在频率跳变阶段运行不稳定。根据实验测量结果，运用瑞利准则分析了产生这一现象的机理，并且提出了控制燃烧器频率跳变的有效方法。

Experimental Study on Frequency Hopping of a Self-excited Pulse Combustor

Frequency hopping phenomenon of a self-excited pulse combustor was experimentally studied and the regular of the frequency hopping with the power and equivalence ratio of this kind of combustor was measured. That is when the power of the combustor decreases to a certain critical value, the operating frequency of the combustor will hop from a fundamental frequency value to a higher harmonic frequency and if the power of the combustor is further decreased, the operating frequency of the combustor will decrease according to acoustics law at this harmonic wave, and vice versa; when equivalence ratio is higher, frequency hopping phenomenon will occur at higher power; too low in equivalence ratio may lead to unstable operation at the frequency hopping process. The mechanism of this phenomenon was analyzed by Rayleigh Criterion based on the experimental measurement results above and the effective controlling methods were presented as well.