微重力下低速空气伴流对甲烷-空气层流扩散火焰特性的影响

研究微重力下空气伴流对层流射流扩散火焰特性的影响，可为航天领域中火灾探测研究提供理论支持。在国家微重力实验室落塔式设施中进行了短时（3.6 s）微重力实验，获取不同伴流空气速度下甲烷火焰的特性。结果表明，层流射流扩散火焰特性会受到微重力环境下低速空气伴流的影响。当气流速度为0~0.5 m/s时，在微重力环境下无法观察到火焰振荡现象，随着伴流速度增加，火焰的长度和直径减小，但是与长度相比，直径没有明显变化；随着伴流速度的增加，微重力环境下甲烷火焰的辐射热损失率降低，而微重力火焰的辐射热损失率比常重力下大。

Effects of low coflow velocity on thecharacteristics of laminar methane-air diffusion flames in microgravity

Research on the effect of air flow with diffusion flame characteristics of laminar jets under microgravity can provide theoretical support for fire detection in aerospace research. A short-term (3.6 s) microgravity experiment was conducted in the Drop tower facility of the National Microgravity Laboratory of China to obtain the characteristics of methane flames under different coflowing air speeds. Preliminary drop tower experimental results showed that characteristics of laminar jet diffusion flames could be affected by low air flow velocities in microgravity environment. The phenomenon of flame oscillation couldn't be observed in microgravity with coflow velocities of 0~0.5 m/s, the luminous flame length and diameter decreased with coflow velocity increasing, but the luminous flame diameter didn't change significantly compared to luminous flame length; the radiative heat loss fraction for the methane-fueled flames in microgravity decreased with coflow velocity increasing, and the radiative heat loss fraction was much larger for flames in microgravity than in normal gravity.