2023 Fiscal Year Final Research Report
Establishment of solid material fire safety evaluation method for manned space activities on the Moon and Mars
| Project/Area Number |
21K18775
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| Research Category |
Grant-in-Aid for Challenging Research (Exploratory)
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| Allocation Type | Multi-year Fund |
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| Review Section |
Medium-sized Section 24:Aerospace engineering, marine and maritime engineering, and related fields
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| Research Institution | The University of Tokyo |
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Principal Investigator |
Nakaya Shinji 東京大学, 大学院工学系研究科(工学部), 准教授 (00382234)
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| Co-Investigator(Kenkyū-buntansha) |
津江 光洋 東京大学, 大学院工学系研究科(工学部), 教授 (50227360)
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| Project Period (FY) |
2021-07-09 – 2024-03-31
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| Keywords | 有人宇宙活動 / 火災安全性評価 / 微小重力環境 / 部分重力環境 / 浮力 / 固体燃焼 |
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| Outline of Final Research Achievements |
In order to evaluate the fire safety of solid plastic materials for manned space activities under partial gravity conditions aiming at the Moon and Mars, combustion experiments were conducted for PMMA rods with diameters of 4 and 6 mm. A combustion vessel was installed in a centrifuge, and the limiting oxygen concentration (LOC) for flammability in opposed-flows under hypergravity environments was investigated. In addition, a LOC model in opposed-flow was developed, considering the energy balance. The model parameters were evaluated using a Bayesian approach: the Markov Chain Monte Carlo method. As a result, we clarified the characteristics of the LOC under hypergravity. It was also shown that the Coriolis force can be negligible near the LOC. Furthermore, predictions of the LOC under partial gravity, such as on the Moon or Mars, showed that it is lower than those in normal gravity and microgravity.
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| Free Research Field |
航空宇宙工学
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| Academic Significance and Societal Importance of the Research Achievements |
近年，月，火星を含む有人宇宙探査が計画されている．有人宇宙活動における火災安全性はこれまで，地上において評価されているが，燃焼現象が微小重力や部分重力環境下の挙動とは異なり，これらの環境下における火災安全性の評価手法が求められていた．本研究で得られた結果やモデルの評価結果は，これらの環境下における火災安全性評価手法の構築に必要な多くの知見を示したのに加え，通常重力と微小重力での結果と比較すると部分重力環境下において最も火災が起きやすいことを示した．また，ベイズ的手法によりモデルの不確定性を示したことにより，今後の実験の必要性について示すことができ，有人宇宙活動の拡大につながる知見を得た．
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