化学当量比对旋流燃烧器热声不稳定特性的影响  

Influence of Equivalence Ratio on Characteristics of Thermoacoustic Instability in a Swirl Combustor

作　　者：李国能[1] 周昊[1] 李时宇[1] 岑可法[1] 

机构地区：[1]能源清洁利用国家重点实验室(浙江大学),浙江省杭州市310027

出　　处：《中国电机工程学报》2008年第8期18-23,共6页Proceedings of the CSEE

基　　金：国家自然科学基金项目(50576081;60534030)~~

摘　　要：为探索旋流燃烧器内热声不稳定的产生机理，搭建了可调型旋流燃烧器热声不稳定试验台架。旋流燃烧器采用燃料风、直流二次风、旋流二次风和高动量三次风的配风结构，燃料风管直径与燃烧腔直径比为0．25。试验测量了旋流燃烧器的温度分布和脉动压力，发现旋流燃烧器热声不稳定的脉动压力可达450Pa，压力幅值随着化学当量比的增大而减小；第1阶共振频率介于187-261Hz之间，随着化学当量比的增大先是减小，随后有一跃升过程，跃升之后随着化学当量比的增大而缓慢增大；第3阶共振频率介于717-805Hz之间；第5阶共振频率介于1178-1326Hz之间，第3阶和第5阶共振频率随着化学当量比的增大而缓慢增大；旋流燃烧器的燃烧火焰面随着化学当量比的增加而不断上移，最高燃烧温度可达1450K。In order to probe into the excitation mechanism of thermoacoustic instability in swirl combustors, an experimental setup has been built including an adjustable swirl combustor. The swirl combustor includes a fuel nozzle, a straight secondary air orifice, three tangential swirl secondary flow pipes, and a high momentum tertiary air jet. The ratio of fuel nozzle diameter to that of combustion chamber is 0.25. The temperature distribution inside the combustion chamber and the fluctuating pressure were measured. The influence of equivalence ratio on characteristics of thermoacoustic oscillations was studied. Experimental results show that the maximum oscillating pressure amplitude is larger than 450 Pa, and that the pressure amplitude decreases with the equivalence ratio. The first order resonant frequency lies between 187 Hz and 261 Hz. As the equivalence ratio increases, the first order resonant frequency decreases firstly and following a sharp jump to a much higher value. At last, it increases slightly with the equivalence ratio, The third order resonant frequency lies between 717 and 805 Hz, and the fifth order one lies between 1 178 and 1 326 Hz, both of which increase slightly with the equivalence ratio. The flame front inside the combustion chamber moves downstream when the equivalence ratio increases. The maximum temperature reaches 1 450 K.

关 键 词：旋流燃烧器 热声不稳定 化学当量比 频谱分析 

分 类 号：TK124[动力工程及工程热物理—工程热物理]