2023-12-04 バージニア工科大学(VirginiaTech)
◆最新の研究では、沸騰水における跳躍する気泡に焦点を当て、これにより表面から効率的に熱を取り除く新しい手法を提案しています。この手法は、気泡を通常の1/10のサイズで放出し、より小さく、より多くの気泡がエネルギーを運ぶことができるようにすることで、表面からの熱の取り除きを向上させています。これにより、熱伝達効率が向上し、データセンターなどでの冷却に革新をもたらす可能性があります。
＜関連情報＞
- https://news.vt.edu/articles/2023/11/eng-me-boreyko-boiled-bubbles-jumping.html
- https://onlinelibrary.wiley.com/doi/10.1002/adfm.202312088
プール沸騰中の合体誘起ジャンピング気泡 Coalescence-Induced Jumping Bubbles during Pool Boiling
Hyunggon Park, S. Farzad Ahmadi, Thomas P. Foulkes, Jonathan B. Boreyko
Advanced Functional Materials Published:03 December 2023
DOI:https://doi.org/10.1002/adfm.202312088
Abstract
Surfaces with micro/nano-structures significantly enhance the critical heat flux of nucleate boiling by increasing the wickability of the liquid phase to delay film boiling. An alternative strategy, of removing surface bubbles at smaller sizes, is largely ignored. Here, they fabricate a rationally designed micro-structured surface that enables the coalescence-induced departure of microscopic vapor bubbles during the pool boiling of water at diameters an order of magnitude smaller than single-bubble buoyant departure. Arrays of micro-cavities or micro-grooves serve as tailored nucleation sites to nucleate close-packed vapor bubbles, which coalesce at unusually small sizes compared to a homogeneous surface. Two different modes of coalescence-induced bubble departure are observed and modeled: capillary-inertial jumping for smaller micro-bubbles and buoyant-inertial liftoff for larger micro-bubbles. Capillarity-enhanced pool boiling on micro-structured surfaces has the potential to dramatically enhance the heat transfer coefficient and critical heat flux of pool boiling.
