缩进深度对同轴式喷嘴流量特性的影响

为研究同轴式喷嘴缩进深度对喷嘴流量和燃烧性能的影响，研究了缩进区内的流动、蒸发和燃烧过程，并建立了理论分析模型。对某同轴式喷嘴的计算表明，计算结果与热试数据相吻合。喷嘴缩进区内液氧蒸发量不超过1．5％。但缩进深度将引入不可忽略的缩进压力损失(本算例混合比为1时，缩进压力损失约为0．6MPa)，并导致喷嘴流量特性发生变化：氢氧喷嘴流量系数随缩进深度增大而减小；氢喷嘴流量系数随混合比增大而减小，氧喷嘴流量系数则反之。缩进区能显著改善气液速度比和动量比，因而有利于雾化、混合和燃烧效率的提高。

Effects of recess on coaxial injector' s discharge coefficient and performance

An analytical model and methodology to characterize the behavior of an atomization and chemical reaction spray produced by a coaxial injector with recessed central tube were presented in this paper. A type of coaxial injector element was calculated using this model. Calculated results of injector discharge coefficients are in rather good agreement with firing data. LOX mass percent vaporized in recession zone is less than 1.5%. Nevertheless, coaxial injector with LOX post recession can significantly change gas-to-liquid injection velocity ratio and momentum ratio, which affects injector combustion performance. Recessing LOX post results in extra recession pressure loss (0.6MPa when MR=1) and variations of injector discharge coefficients of oxidizer and fuel.