Novel evaluation methodology of burning character of thermoplastic material using low pressure

2022 Fiscal Year Final Research Report

• Project/Area Number: 20H02397
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 25020:Safety engineering-related
• Research Institution: Toyohashi University of Technology
• Principal Investigator: NAKAMURA YUJI 豊橋技術科学大学, 工学(系)研究科(研究院), 教授 (50303657)
• Co-Investigator(Kenkyū-buntansha): 松岡 常吉 豊橋技術科学大学, 工学(系)研究科(研究院), 准教授 (90633040)
• Project Period (FY): 2020-04-01 – 2023-03-31
• Keywords: 熱可塑性樹脂 / 燃焼 / 火災 / 溶融 / 突沸 / 移動数 / 燃焼特性

Outline of Final Research Achievements

With direct numerical simulation of melting/gasification model of thermoplastic polymers, it was clearly shown that the dynamics of molten matter largely alter the combustion character (ignition etc). To avoid such dynamical effect and bubble bursting, shell-structured 1-D spherical combustion system over a polymer in low pressure has been developed. With detail temperature measurement, it is understood that modified transfer number (B-number) is measured in satisfactory level of accuracy. In fact the burning character is quite similar to what has been reported with microgravity (1-D) test results. In order to compare in a precise manner, microgravity combustion chamber to perform droptower test is developed. Through the microgravity experiments, it was notified that d-square law is satisfactory presented, however, bubble bursting is found to fail to suppress even the shall-structure is employed. Precise understating of bubble formation/bursting is seriously required.

Free Research Field

火災

Academic Significance and Societal Importance of the Research Achievements

溶融とガス化を含めたプラスチックの非定常流動問題を数値的に解く手法の開発を行い，溶融挙動により着火タイミングが大きく影響を受けることを明らかにした．また３D観測可能な可視化法の開発により，流動が燃え拡がり現象にも影響することがわかった．
そのような流動効果を抑制させるべく，グラスホフ数近似を用いて煤と無関係な熱可塑性高分子（プラスチック）の一次元燃焼特性を得る方法論を提供した．この提案は，燃焼問題で課題となる次元を落とす「簡略化」に役立つという学術的意義をもたらすだけでなく，プラスチックの燃焼性評価の精度向上に資するものであり，将来的には燃焼特性の標準化に資するものとなり得る．