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为了解液氧/甲烷火焰在外界扰动作用下的表现,增进对燃烧不稳定性的理解,分别对两种喷剪切同轴式喷嘴结构进行了试验,试验采用单喷嘴矩形模型燃烧室,液氧以液态从中心喷嘴喷注,甲烷以气态从同轴的环形腔喷注。试验中,压力调节装置上的齿轮间断性地堵住和打开安装在燃烧室底部和主喷管旁边的辅助喷管出口,分别向燃烧室输入高频扰动。采用高速照相机记录火焰的OH辐射量,并采用阴影和纹影技术记录液氧的喷雾过程。试验成功激发起了燃烧室一阶横向和一阶纵向振型,在高频扰动作用下,还产生了两次强低频振荡。讨论了分离火焰的特征及其液氧射流在外界扰动作用下的表现和影响参数。
In order to understand the performance of the liquid oxygen / methane flame under disturbance and to improve the understanding of combustion instability, two kinds of coaxial nozzle structures of spray-jet cutting were tested respectively. The single-nozzle rectangular model combustion chamber, liquid Oxygen is injected in a liquid state from a central nozzle and methane is injected in a gaseous state from a coaxial annular chamber. In the test, the gear on the pressure regulating device intermittently blocked and opened the auxiliary nozzle outlet installed at the bottom of the combustion chamber and beside the main nozzle, respectively inputting the high-frequency disturbance to the combustion chamber. High-speed cameras were used to record the OH radiation of the flame and the shading and profiling techniques were used to record the spray of liquid oxygen. The experiment successfully stimulated the first-order horizontal and first-order longitudinal modes of the combustion chamber. Under the action of high-frequency disturbance, two strong low-frequency oscillations were produced. The characteristics of the separation flame and the performance and influence parameters of the liquid oxygen and oxygen jets under disturbance are discussed.