Evaluation and modeling of two-phase flows in a liquid metal under a magnetic field using a high-speed ultrasonic tomography

2023 Fiscal Year Final Research Report

• Project/Area Number: 21H01250
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 19010:Fluid engineering-related
• Research Institution: Kobe University
• Principal Investigator: Murakawa Hideki 神戸大学, 工学研究科, 准教授 (40467668)
• Co-Investigator(Kenkyū-buntansha): 齊藤 泰司 京都大学, 複合原子力科学研究所, 教授 (40283684) ; 杉本 勝美 神戸大学, 工学研究科, 助教 (40420468)
• Project Period (FY): 2021-04-01 – 2024-03-31
• Keywords: 液体金属 / 水平磁場 / 気泡 / ボイド分布 / 超音波トモグラフィ

Outline of Final Research Achievements

The study experimentally investigated the effects of a horizontal magnetic field (MF) on the behavior of bubble chains in a gallium alloy. High-speed ultrasonic tomography was used to measure the instantaneous bubble crossing positions in a cylindrical column with an inner diameter of 50 mm. With an increase in the MF strength, the oscillations of the bubbles were suppressed, resulting in the crossing position being concentrated in a certain area of the cross-section. The fluctuations in the time intervals of the chain bubbles decreased. These effects were more pronounced when the Stuart number was greater than 1. The distribution of bubbles in the direction perpendicular to the MF was widespread slightly compared to that in the direction parallel to the MF; this was noticeable at higher flow rates.

Free Research Field

熱流体

Academic Significance and Societal Importance of the Research Achievements

磁場印加時の液体金属中の気泡挙動を実験的に評価することは、連続鋳造における製品品質の向上に寄与する。しかしながら流体が不透明であることから、液体金属中の二相流動の実験的評価は困難であり、十分な実験データが無かった。本研究では、超音波トモグラフィ法を用いることで内径50mmの円筒容器内を上昇する気泡を対象に、気泡分布に与える磁場の影響を実験的に解明した。これらの結果は、気液密度比や表面張力が従来の流体と大きく異なる液体金属において、気泡の合体や分裂といった複雑な二相流の解明に貢献し、数値解析に必要とされる構成方程式の精度向上に寄与する。