半封闭狭窄通道内甲烷/空气预混火焰传播不稳定性实验研究

针对贫油预混预蒸发燃烧室主燃级中横喷液雾现象进行研究，综合考虑RP-3航空煤油横喷液雾的雾化、蒸发和自燃过程构建自燃预测模型，基于CH基团随时间的变化规律对自燃延迟时间进行预测。结合试验测试结果对模型进行校验，并进一步分析温度、压力、流速、射流动量比等变量对自燃延迟时间的影响规律。结果表明：对于直射式喷嘴形成的横喷液雾，其下游的油气分布主要受射流动量比和流动速度的影响，射流动量比决定了液雾的总体油气比，流动速度则主要影响液滴的粒径及其蒸发时间；随着压力、射流动量比及气流速度的增加，自燃延迟时间均会缩短，相比于预混燃料液雾的自燃延迟时间受负温度效应的影响较弱。

Experimental study on propagation instabilities of premixed methane/air flames in a semi closed narrow channel

A phenomenon of liquid jet in cross flow in fuel lean premixed pre evaporation combustor main stage was studied. The autoignition prediction model was constructed with considering the atomization, evaporation and autoignition process of liquid jets in cross flow for RP 3 jet fuel sprays, eventually the autoignition delay time was predicted based on the time evolution of the CH in the liquid gas mixture. The model was validated by comparing to experimental results and was then utilized to analyze the influences of variables such as temperature, pressure, main stream velocity and liquid to air momentum ratio on the autoignition delay time. The results show that for liquid jet in cross flow formed by direct injection type nozzle, its fuel air mixing downstream is mainly affected by the liquid to air momentum ratio and main stream velocity, in which liquid to air momentum ratio determines total fuel air ratio, while stream velocity mainly affects the droplet sizes and the related evaporation time; the autoignition delay time decrease with the increase of pressure, liquid to air momentum ratio and main stream velocity. The autoignition delay time of spray is less affected by the negative temperature effect compared to premixed combustibles.