Analysis of condensed phase reaction in successive fragmentation of metal droplets by high-speed temperature measurement and Infi-TOF

2023 Fiscal Year Final Research Report

• Project/Area Number: 22K18771
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Review Section: Medium-sized Section 19:Fluid engineering, thermal engineering, and related fields
• Research Institution: Kyushu University
• Principal Investigator: Inoue Chihiro 九州大学, 工学研究院, 准教授 (70466788)
• Co-Investigator(Kenkyū-buntansha): 王 振英 九州大学, 工学研究院, 助教 (20896633)
• Project Period (FY): 2022-06-30 – 2024-03-31
• Keywords: 金属液滴 / 液滴 / 連鎖分裂 / 熱物質拡散 / 表面張力 / 高速度可視化 / 数理モデル / 凝縮相

Outline of Final Research Achievements

According to conventional knowledge of fluid engineering, each droplet splits only once. In contrast, a successive fragmentation phenomenon has recently been discovered in which a condensed phase reaction inside a melt droplet produces an internal inflating bubble, causing the droplet to break up to ten times. However, the fundamental question of why the successive cascade occurs remains unanswered. In this study, the mechanism of metal droplets was investigated using a combined analysis method that synchronizes high-speed temperature measurement using the two-color temperature method and in-situ analysis of the gas species generated.

Free Research Field

流体工学・熱工学

Academic Significance and Societal Importance of the Research Achievements

通常，液体や固体に外力を加えると分裂するが，その回数は1回程度に限られる．対して，炭素鋼やチタンなどの金属液滴は，繰り返し分裂することが知られているものの，その流体力学的機構は未解明であった．本研究は，物理的・科学的実験を通して，金属液滴の連鎖分裂が，雰囲気からの物質拡散によって律速されることを実験と理論から明らかにした．連鎖分裂は，高効率に微小液滴および粉末を製造できることから，近年需要が高まっている金属微粒子製造技術への応用が期待され，本研究によって，その原理的な成立性を実証した．