Fundamental Research on Flame Spread over Condensed Phase Combustibles for Fire Safety Assessment of Low and Super Gravity Environments

为了建立空间飞行任务的火灾安全评估，对不同重力环境下凝聚相材料上的火焰传播进行研究是非常重要的。在本研究中，落塔、转臂装置及配重系统分别进行微重力测试、超重力测试及失重测试。从而明确了可燃固体和液体在不同重力水平、微重力(10^&lt；-5&gt；G)、低重力(0.5~0.9G)和超重力(2~5G)下的火焰传播速率。提出了利用重力效应与常压下稳定火焰传播的限氧效应的相似性进行火灾安全评价的简便方法。阐明了微重力条件下在热稀薄可燃固体上传播火焰的氧气浓度极限与空间火灾灭火的反向流速之间的关系。

In order to establish the fire safety assessments for space mission, investigation of flame spread over condensed phase materials in various gravity environments is important. In this study, a drop tower, a rotating arm facility and the drop tower with counterweight system are used for a microgravity test, a super gravity test and a low gravity test, respectively. As a result, we have clarified the flame spread rates of the combustible solid and liquid in various gravity levels, microgravity (10^<-5> G), low gravity (0.5～0.9 G) and supergravity (2～5 G). Moreover, we have proposed the simple method of fire safety assessment using the similarity between the gravity effect and the oxygen restriction effect on steady flame spread under normal gravity. And the relationship between the oxygen concentration limit for spreading flame over thermally thin combustible solid under microgravity condition and the opposed flow velocity has also been clarified for extinguishments of space fire.