Combustion of solid material under microgravity -In case of porous material-

固体材料在微重力下的燃烧-多孔材料的情况-

• 批准号: 04452143
• 负责人: ITO Kenichi
• 金额: $ 4.42万
• 依托单位: Hokkaido University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (B)
• 财政年份: 1992
• 资助国家: 日本
• 起止时间: 1992 至 1994
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-04452143/
• 关键词: Combustion; Solid material; Microgravity; Porous material; Fire safety; Flame propagation speed; Natural convection; Pyrolysis; 微小重力環境; 固体の燃焼; 多孔性材料; 火炎伝ぱ; 着火; 発泡ポリスチレン; 宇宙環境利用; ふく射; 無重力; 固体燃焼; 宇宙火災; 火災; 自由落下

Natural convection caused by gravity field makes the combustion phenomena complicated. Since solid combustion is constituted by many physical processes, microgravity field is quite helpful to study its combustion processes through the elimination of natural convection.In the first year of this project microgravity experimental technique have been developed by using three types of drop tower, 5m, 50m and 500m drop towers. The flame propagation speed of cotton strings and paper sheet has been successfully measured.In the second year, the effect of various parameters, such as oxygen concentration, and dimension of test pieces have been investigated. The smaller amount of required oxygen, the higher propagation velocity. The higher oxygen concentration also gave the higher propagation velocity. The matrix of paper sheet, simulation of porous material, has also burned to examined the effect of pore size inside of the material, ventilation availability and oxygen concentration. Under microgravity these parameters except oxygen concentration did not affect to the flame propagation speed while they had strong effect under normal gravity. This is because these parameters have effect on the combustion through the change of natural convection strength inside the material.In the final year, the combustion of polystirene foam beads, which is made from a single chemical component have been investigated to hnow the dominant factors of porous material combustion. The results showed that flame spread phenomena of solid material is mainly dominated by the rates of heat supply to the unburned region and oxygen supply to combustion region. When the former factor, heat supply, is more dominant flame propagation is easier under microgravity because heat is not taken away by natural convection. When the later factor is dominant, flame propagation is faster under normal gravity with aid of natural convection to supply oxygen.

重力场引起的自然对流使燃烧现象变得复杂。由于固体燃烧是由许多物理过程构成的，微重力场通过消除自然对流来研究其燃烧过程非常有帮助。在该项目的第一年，利用5m、50m和500m三种落塔塔开发了微重力实验技术。已经成功测量了棉线和纸片的火焰传播速度。第二年，研究了各种参数（例如氧气浓度和试件尺寸）的影响。所需氧气量越少，传播速度越高。氧气浓度越高，传播速度也越高。模拟多孔材料的纸张基体也被燃烧，以检查材料内部孔径、通风可用性和氧气浓度的影响。在微重力条件下，除氧浓度外，这些参数对火焰传播速度没有影响，而在正常重力条件下，这些参数对火焰传播速度有很强的影响。这是因为这些参数是通过改变材料内部自然对流强度来影响燃烧的。去年，对由单一化学成分制成的聚苯乙烯泡沫珠粒的燃烧进行了研究，以了解多孔材料燃烧的主导因素。结果表明，固体材料的火焰蔓延现象主要受未燃区供热量和燃烧区供氧率的影响。当前一个因素（供热）占主导地位时，在微重力下火焰传播更容易，因为热量不会被自然对流带走。当后者占主导地位时，在正常重力下借助自然对流提供氧气，火焰传播更快。

项目成果

KITO et al: "Prelimiuary Experiments on Solid Conhustion in Microgravity at JAMIC drop fube" Proc:18th International Symposium on Space Techuology and Scieuce. 2295-2301 (1992)

KITO 等人：“JAMIC drop fube 微重力固体混合的初步实验”Proc：第 18 届国际空间技术与科学研讨会。