摘要
通过高频粒子图像测速法(particle image velocimetry,PIV)及高速相机、压力传感器、光电倍增管等,研究中心分级燃烧器流-热-声动态特性,揭示了中心分级燃烧器单级旋流和中心分级火焰的流动及热声稳定性的变化规律。结果表明:主燃级为旋流火焰时,预燃级的旋流空气会破坏流场中的回流区,加剧主燃级火焰的不稳定性,而预燃级为旋流火焰时可将主燃级火焰的脉动压力幅值降低76.8%;燃烧热负荷增大导致气流加速膨胀,诱发射流剪切层产生更高强度的旋涡,预燃级与主燃级火焰相互干涉可加速旋涡的耗散,改变了旋涡的脱落频率;与单级旋流火焰相比,主燃级和预燃级火焰干涉区的火焰脉动最剧烈,且主燃级射流外剪切层的大尺度旋涡加剧了主燃级火焰的脉动。
[Objective]To reveal the influence of interaction between pilot and main flames on flow and thermoacoustic instability characteristics,the flow and thermoacoustic dynamic characteristics of the pilot stage,main stage,and centrally staged flames in the combustion chamber of the central staged model combustor are studied in detail through experiments.[Methods]High-speed measurement methods such as high-frequency particle image velocimetry,high-speed camera,pressure sensors,and photomultiplier tube are used to study the flow-flame-acoustic dynamic characteristics of the central staged burner.During the experiments,the unsteady flow field,flame CH*signal distribution,global heat-release rate,and pressure pulsation characteristics are measured under different testing conditions.[Results]The results showed that the pilot swirling jet had a significant influence on the flow-flame-acoustic dynamic characteristics of the stratified burner.Furthermore,when the pilot stage used a swirling flame,the main recirculation zone was formed downstream of the nozzle outlet and the high-temperature burned gas was rolled back to improve the combustion stability of the swirl flame.The peak value of pressure was 683 Pa,and the main peak values of dynamic pressure and heat release were both visible at a frequency of 120 Hz.However,the dominant frequency of the flow field proper orthogonal decomposition(POD)time coefficient spectrum showed that the dominant frequencies of large-scale shedding vortex in the flow field were 68 and 109 Hz,indicating that the interaction between pilot and main flames caused the thermoacoustic instability frequency to be inconsistent with large-scale vortex shedding frequency.Moreover,the dominant frequency of pressure and heat release were slightly shifted when the pilot stage was operated with a swirling air jet,and it was reduced by 5 Hz and got to 115 Hz.However,the main recirculation zone disappeared,resulting in a strengthening of the thermoacoustic instability and an increase in the peak pressure to 294
作者
金明
陆羽笛
李原森
柳伟杰
葛冰
臧述升
JIN Ming;LU Yudi;LI Yuansen;LIU Weijie;GE Bing;ZANG Shusheng(School of Mechanical Engineering,Shanghai Jiao Tong University,Shanghai 200240,China;Aero-Engine Academy of China,Aero Engine Corporation of China,Beijing 101304,China)
出处
《清华大学学报（自然科学版）》
EI
CAS
CSCD
北大核心
2024年第1期99-108,共10页
Journal of Tsinghua University(Science and Technology)
基金
国家自然科学基金资助项目(51876123)
国家科技重大专项(HT-J2019-III-0020-0064)
