Experimental study on ignition and blowout characteristics of dual combined flame stabilizers in scramjet
Experimental study on ignition and blowout characteristics of dual combined flame stabilizers in scramjet
复制标题
DOI：
10.1016/j.ast.2023.108634
复制
发表时间：
2023-09
影响因子：
5.6
通讯作者：
Fei Qin;Xingliang Chen;Shao-hua Zhu;Bing Liu;Jingyu Zhang;Yi Gao;Li Tan
中科院分区：
文献类型：
--
作者：
Fei Qin;Xingliang Chen;Shao-hua Zhu;Bing Liu;Jingyu Zhang;Yi Gao;Li Tan
超燃冲压发动机的点火和熄火特性对超燃冲压发动机的性能和工作极限有着重要的影响。在这项研究中，一个典型的超燃冲压发动机燃烧室的直连地面试验已经进行了模拟高空飞行条件下的马赫数为6。进入的空气具有1689 K的总温度和30 kPa的动压。得到了双支板/凹腔组合火焰稳定器在超燃冲压发动机中的点火和熄火特性。利用关键部位压力的即时响应分析了点火过程中压力的前向传播特性和火焰熄灭过程中的压力变化。通过高速摄影、OH自由基自发辐射摄影、光谱仪和多光谱成像等设备，获得了点火和熄火过程中的火焰分布和温度变化。结果表明，从局部点火到整体点火的过程持续数百毫秒，包括四个阶段和两个压力提升阶段。火焰向前扩散和上游空腔成功点火是主要过程，分别占燃烧时间的60%和30%。在点火过程中，两级空腔的压力响应时间相差几毫秒。并且火焰通过燃烧室壁向前传递到上游空腔。在高当量比（ER）条件下，随着点火过程的进行，火焰稳定模式从稳定空腔回流区火焰转变为稳定支柱剪切层火焰。在整体点火完成后，凹腔上游剪切层处的火焰温度超过2700 K，但随着ER减小，核心反应区从支杆顶部向凹腔尾部和底部移动，火焰温度降至2125 K。火焰熄灭过程中出现两次压降，全局熄灭的临界ER约为0.33。在第一次压降过程中，主剪切层火焰被吹灭，空腔火焰强度减弱。最后，第二个压力降发生在空腔中的火焰向下游移动并熄灭时。
The ignition and blowout characteristics have a significant impact on the performance and operating limit of the scramjet. In this study, direct-connected ground tests of a typical scramjet combustor have been conducted to simulate the high-altitude flight condition of Mach 6. The incoming air has a total temperature of 1689 K and a dynamic pressure of 30 kPa. The ignition and blowout characteristics of the dual strut/cavity combined flame stabilizers in the scramjet are obtained. The immediate response of pressure at key positions is used to analyze the forward propagation characteristics of pressure during the ignition process and the pressure variation during the flame blowout process. The flame distribution and temperature variation during the ignition and blowout processes are obtained by high-speed photography, OH⁎spontaneous radiation photography, spectrometer and multispectral imaging equipment. Results indicate that the process from local ignition to global ignition successfully has durations lasting for hundreds of milliseconds, comprising four stages with two pressure lift stages. The flame diffusing forward and upstream cavity igniting successfully are the main processes, constituting 60% and 30% of the duration, respectively. During the ignition process, the pressure response time of the two-stage cavity differs by several milliseconds. And the flame is transmitted forward to the upstream cavity through combustor walls. As the ignition process progresses under high equivalent ratio (ER) conditions, flame stabilization mode shifts from stabilizing flame in the recirculation zone of the cavity to stabilizing flame in the shear layer of the strut. Upon completion of global ignition, the flame temperature at the shear layer of the cavity upstream exceeds 2700 K, but decreases to 2125 K as the core reaction zone is shifted from the top of the strut to the tail and bottom of the cavity when theERdecreases. Two pressure drops occur during the flame blowout process, and the criticalERof the global blowout is approximately 0.33. The primary shear layer flame is blown out during the first pressure drop, and the intensity of the cavity flame decreases. Finally, the second pressure drop occurs as the flame in the cavity moves downstream and extinguishes.