Clarification of small ice particles motion during water freezing using Near Infrared camera and dissipative particle dynamics simulations

2020 Fiscal Year Final Research Report

• Project/Area Number: 19K14886
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 19010:Fluid engineering-related
• Research Institution: Nagoya Institute of Technology
• Principal Investigator: Yamada Toru 名古屋工業大学, 工学(系)研究科(研究院), 助教 (40772067)
• Project Period (FY): 2019-04-01 – 2021-03-31
• Keywords: 水 / 凍結 / 近赤外線 / 水の近赤外吸光特性 / 数値計算 / 散逸粒子動力学法 / 計算誤差 / 画像解析

Outline of Final Research Achievements

This study implemented both experiments and numerical simulations, aiming at clarifying the motion of small ice particles during water freezing at microscales and their effects on the phenomenon. In the experiments, the identification of water-ice interface and the image analysis of the particle behavior were performed for one dimensional freezing in a microchannel. In the simulation, the evaluation of quantities related to physical properties in dissipative particle dynamics was performed to improve its reliability.
First, two techniques were proposed which make it possible to identify the interface and to analyze the particle behavior in a non-contact manner. These techniques were used to quantitatively analyze the freezing phenomenon. Second, the numerical error of shear stress for different time steps were investigated, and the results showed that the tendency was different from that of temperature which was usually used for the error estimation in DPD simulations.

Free Research Field

流体工学　伝熱工学

Academic Significance and Societal Importance of the Research Achievements

水の凍結は様々な工業製品（例えば航空機，熱交換器）の性能を劣化させる要因となる．これを抑制するため，近年では，微細表面加工技術の発展による過冷却促進壁面，すなわち不凍面製造技術の開発が注目があつまっている．これらの技術を後押しするために学術的視点からの基礎研究は不可欠である．本研究では，過冷却水の凍結現象と従来の凍結の違いは何か，という学術的な視点から考察するため，微小な空間における非接触測定技術を提案し，この実用性を確認することから開始し，本研究を通して本技術の実用性を示した．本技術により，本現象の基礎研究のさらなる進歩および上述の機器の性能向上が見込まれる．