缩进长度对同轴离心式喷嘴燃烧稳定性的影响  

Effects of recess length on combustion stabilities of swirl coaxial injectors

作　　者：杨尚荣 吴林龙 李娜 王勇 杨宝娥 YANG Shangrong;WU Linlong;LI Na;WANG Yong;YANG Baoe(Science and Technology on Liquid Rocket Engine Laboratory,Xi’an Aerospace Propulsion Institute,Xi’an 710100,China)

机构地区：[1]西安航天动力研究所液体火箭发动机技术重点实验室,陕西西安710100

出　　处：《推进技术》2024年第7期135-143,共9页Journal of Propulsion Technology

基　　金：国家自然科学基金(51606138)。

摘　　要：针对缩进长度对气体中心液体离心式同轴(GCLSC)喷嘴(简称同轴离心式喷嘴)燃烧稳定性的影响,开展富氧气/煤油同轴离心式单喷嘴燃烧稳定性实验研究。通过改变燃料和氧化剂喷射速度,获得了三种缩进长度喷嘴(8,10,12 mm)的稳定性图或稳定性边界。利用高速相机拍摄了火焰的CH*自发光图像,通过动力学模态分解(DMD)方法分析了燃烧流场的空间结构。研究发现:当氧化剂速度足够高时,三种缩进长度喷嘴均出现了不稳定燃烧。燃料速度≤11 m/s时,滞后区域较窄或不存在,燃料速度>11 m/s,滞后区域变宽。10 mm缩进长度喷嘴的稳定性边界最大,滞后边界在燃料速度≤11 m/s时最大。相比稳定燃烧状态火焰长度,发生不稳定后,火焰长度显著缩短,且在横向扩展。三种缩进长度喷嘴在稳定和不稳定燃烧状态下,CH*自发光均紧贴喷嘴出口,说明燃烧在缩进室内部便已开始。一阶切向不稳定对应的DMD模态应为流向涡和角向涡耦合产生的螺旋形不稳定涡结构。Effects of recess length on combustion stabilities of the gas-centered liquid-swirl coaxial injec-tors were experimentally studied using a single injector with oxygen-rich air/kerosene.By changing the injection velocity of fuel and oxidizer,the stability maps of three injectors with different recess lengths(8,10,12 mm)were obtained.The CH*chemiluminescence images of the flame were taken with a high-speed camera and were analyzed by the dynamic mode decomposition(DMD)method.It is found that when the oxidizer velocities are high enough,all three injectors exhibit spontaneous combustion instability.When the fuel velocities are less than 11 m/s,the hysteresis regions are narrow or absence,and when the fuel velocity is greater than 11 m/s,the hys-teresis regions become wider.The stability boundary of the injector with 10 mm recess length is the largest,and the hysteresis boundary is the largest when the fuel velocity is less than 11 m/s.Compared with the flame lengths of stable combustion states,the flame lengths are significantly shortened after the occurrence of instabilities,and they expand laterally.Under both conditions,CH*chemiluminescences are attached to the injector outlet,indi-cating that combustion starts in the recess chamber under three recess lengths.The DMD modes corresponding to the first order tangential instability are the spiral unstable vortices generated by the coupling of the streamline vor-tices and the azimuthal vortices.

关 键 词：同轴离心式喷嘴 缩进长度 燃烧稳定性 动力学模态分解 螺旋形涡 

分 类 号：V231.1[航空宇航科学与技术—航空宇航推进理论与工程]