Significant enhancement of critical heat flux with three-dimensional porous-media manufacturing and surface modification technologies of heat-transfer surface structure

2023 Fiscal Year Final Research Report

• Project/Area Number: 21K04945
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 31010:Nuclear engineering-related
• Research Institution: Waseda University
• Principal Investigator: Furuya Masahiro 早稲田大学, 理工学術院, 教授 (80371342)
• Project Period (FY): 2021-04-01 – 2024-03-31
• Keywords: 沸騰熱伝達 / 冷却 / 限界熱流束 / 付加造形 / 親水性

Outline of Final Research Achievements

Pool-boiling heat-transfer experiments were conducted with three-dimensional additive-manufactured helix structures on the heat-transfer surface. The results showed that the critical heat flux increased by 40% when the helix pitch was long. The critical heat flux decreased by 30% when flake-like materials or spheres were installed, but the critical heat flux reversed and increased by 30% when the surface became hydrophilic. Furthermore, the critical heat flux was increased by a factor of three by combining the honeycomb porous plates with the lattice structure. The heat transfer enhancement and critical heat flux increase effects are considered to be caused by the increase in the interfacial area concentration by suppressing the coalescence of bubbles and the increase in the liquid supply to the heat transfer surface by increasing the driving force of natural circulation around the heat transfer surface. The mechanistic model developed confirms the proposed principle.

Free Research Field

熱工学

Academic Significance and Societal Importance of the Research Achievements

3Dプリンターによる三次元付加造形技術はより自由に複雑な形状を造形できる。本研究では、プラントや電子回路などで高い熱負荷を受ける面に設置することで冷却性能と冷却限界の両方を向上させることができる形状を探索した。実験の結果、らせん構造やハニカム多孔質体、並びに格子構造を組み合わせた構造が最適で、さらに表面に親水性を付与することで冷却性能と冷却限界が向上することを解明した。発生する気泡の合体を抑制し、伝熱面への冷却水量を増加させることで向上効果がもたらされる原理をシミュレーションで確認した。