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为了研究在总温846K,总压0.7MPa,入口来流马赫数2.1的超声速来流条件下凹腔主动喷注对点火过程的影响,利用高速摄影相机进行观测,对比了凹腔前壁喷注、后壁面喷注等组合喷注方式下开展的发动机乙烯点火试验。基于对高速摄影图像处理的统计分析,研究发现在点火工况条件下,凹腔后壁面喷注相比于前壁喷注更容易使整个凹腔内形成稳定的火焰,当凹腔主动喷注当量比达到0.03时就能使凹腔内形成稳定的火焰;在凹腔后壁面喷注的条件下,当凹腔主动喷注当量比达到0.06,全局当量比达到0.17时,火焰就会穿过剪切层引燃凹腔下游横向射流,在整个发动机中稳定燃烧;凹腔前壁喷注和后壁面喷注相结合的喷注方式能进一步促进初始火核的形成与传播,当凹腔主动喷注当量比达到0.05,全局当量比达到0.16时,火焰就能穿过剪切层引燃凹腔下游横向射流,在整个发动机中稳定燃烧。
In order to study the influence of the active injection of the concave cavity under the condition of the supersonic incoming flow Mach number 2.1 at the total temperature of 846K, the total pressure of 0.7MPa and the inlet flow Mach number of the inlet stream, the observation was made by using a high-speed photographic camera, , Rear wall injection and other combinations of injection engine carried out under the ignition of ethylene test. Based on the statistical analysis of high-speed photographic image processing, it is found that under the ignition condition, the injection of the back wall of the cavity is more likely to form a stable flame in the whole cavity than the injection of the front wall. When the cavity is actively injected When the equivalence ratio reaches 0.03, a stable flame will be formed in the cavity. When the ratio of the active cavity injection equivalent reaches 0.06 and the global equivalent ratio reaches 0.17, the flame will pass through The shear layer ignites the downstream lateral jet of the cavity and stably burns in the whole engine. The injection method combining the injection of the cavity front wall and the injection of the back wall wall can further promote the formation and propagation of the initial nucleus. When the cavity is active When the injection equivalence ratio reaches 0.05 and the global equivalence ratio reaches 0.16, the flame can pass through the shear layer to ignite the downstream lateral jet of the cavity and burn steadily throughout the engine.