Physical modelling for building new method to control unsteady thermocapillary convection in order to create single crystals of high quality

2019 Fiscal Year Final Research Report

• Project/Area Number: 17K14611
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Thermal engineering
• Research Institution: Tokyo Metropolitan College of Industrial Technology
• Principal Investigator: Kudo Masaki 東京都立産業技術高等専門学校, ものづくり工学科, 准教授 (60634524)
• Project Period (FY): 2017-04-01 – 2020-03-31
• Keywords: 単結晶高品位化 / 非定常表面張力差対流 / 物理モデリング / 対流場，温度場 / 数値シミュレーション / 粒子画像流速計

Outline of Final Research Achievements

Thermal and flow fields of full-zone (FZ) liquid bridge were investigated carefully to construct a physical model of FZ liquid bridge for a flow control system. By investigating the spatiotemporal structures of thermal and flow fields, we observed different oscillatory modal structure and Fourier spectrum in upper and lower liquid bridge. Moreover, to construct the physical model, we introduced a numerical simulation (CFD) and a Particle Imaging Velocimetry (PIV) for obtaining broader and more detailed thermal and flow field. “Thin liquid layer model” was also introduced, because it is appropriate as a basis for making a reduced-order model (ROM) and a data assimilation. Broad and detailed thermal and flow field were obtained in the thin liquid layer model, then know-how to introduce CFD and PIV to the FZ liquid bridge was acquired. We achieved significant results for paving the way to make practical physical model.

Free Research Field

流体力学，伝熱工学

Academic Significance and Societal Importance of the Research Achievements

非定常な温度差マランゴニ対流に対して効果的な制御手法を確立するために対流場と温度場を詳細に調査し，制御用の物理モデルの構築の道筋をつけることができた．以上の成果は，FZ法の技術レベル向上に大きく貢献する．これにより半導体，レーザ，LED，二次電池材となる単結晶の高品位化，低コスト化が実現されることで，先端産業の発展に大きく貢献する．また，マランゴニ対流のメカニズム解明は界面における熱流体力学の学術的発展に大きく寄与する．界面における熱流体力学は省エネ，環境問題の解決に不可欠な分野であり，世界中で精力的に研究されている．以上の点から，本研究の社会的波及効果は極めて大きい．