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为研究煤油同轴离心喷嘴的超临界燃烧与火焰特性以及缩进比对燃烧及稳定性的影响,在煤油超临界条件下进行了不同缩进比喷嘴的燃烧实验,实验采用单喷嘴矩形燃烧室,空气和氧气混合物以气态从同轴喷嘴的中心喷嘴喷注,煤油以液态从同轴喷嘴的离心喷嘴喷注,实验利用采样频率为36k Hz的彩色高速CCD相机成功观测到煤油超临界燃烧现象。煤油同轴离心喷嘴超临界燃烧火焰总体呈圆柱射流状;缩进比较大喷嘴的火焰图像中,喷嘴出口为半透明的“稠密”气状射流,未观测到明显的雾化破碎过程;喷嘴缩进比为1.62时火焰较窄且出现火焰团间歇性脱落情况;缩进比对燃烧和燃烧稳定性均有影响,存在相对最佳值使燃烧较稳定。
In order to study the supercritical combustion and flame characteristics of kerosene coaxial centrifugal nozzle and the effect of indentation ratio on combustion and stability, different injections were made under the supercritical conditions of kerosene. The experiment uses single nozzle rectangular combustion chamber The mixture of air and oxygen was injected in a gaseous state from the center nozzle of a coaxial nozzle. The kerosene was injected in liquid state from a centrifugal nozzle of a coaxial nozzle. The experiment successfully observed the kerosene supercritical combustion phenomenon with a color high-speed CCD camera with a sampling frequency of 36 kHz . The flame of the supercritical combusting jet of the kerosene coaxial centrifugal nozzle is generally cylindrical in shape. In the flame image of the larger nozzle, the exit of the nozzle is a translucent “dense” gas jet, and no obvious atomization and fragmentation process is observed. When the nozzle retraction ratio is 1.62, the flame is narrower and the flame groups intermittently come off. The retraction ratio has an impact on the combustion and combustion stability, and the relative best value exists to make the combustion more stable.