Liquid‐Superspreading‐Boosted High‐Performance Jet‐Flow Boiling for Enhancement of Phase‐Change Cooling

Abstract

Enhanced boiling heat transfer via surface engineering is a topic of general interest for its great demand in industrial fields. However, as a dynamic interfacial phenomenon, a deep understanding of its process and mechanism, including liquid re-wetting and vapor departure, is still challenging. Herein, a micro-/nanostructured Cu surface containing a periodic microgroove/pyramid array with rich nanowrinkles is designed, where superspreading (<134.1 ms) of organic cooling agents highly boosts the liquid re-wetting process, causing a discontinuous solid-liquid-vapor three-phase contact line and ultralow under-liquid bubble adhesion force (≈1.3 μN). Therefore, a characteristic, ultrafast jet-flow boiling (bubbles rapidly ejected in multiple strips) is obtained on this surface, giving a priority to nucleation (superheat ≈ 1.5 °C) and simultaneously enhancing the critical heat flux and heat-transfer coefficient by up to 80% and 608%, respectively, compared with a flat surface. In situ observation and analysis of the nucleation, growth, and departure of micro-sized jet-flow bubbles reflects that microgrooves/pyramids with nanowrinkles promote the latent heat exchange process by superspreading-induced ultrafast liquid re-wetting and constant vapor film coalescing. Based on the designed structures, high-performance phase-change cooling for central processing unit heat management in supercomputer centers is accomplished with an ultralow power usage effectiveness (PUE < 1.04).

Superior Heat and Mass Transfer Performance of Bionic Wick with Finger-like Pores Inspired by the Stomatal Array of Natural Leaf

“…The vapor generated within the bionic wick can be expelled through the pore array, effectively reducing vapor transport resistance. Additionally, the capillary structure or surface microstructure plays a crucial role in enhancing the boiling process by facilitating the timely discharge of steam and replenishment of liquid, − demonstrating the importance of structural design in achieving efficient boiling heat transfer. In the context of LHPs, efficient boiling heat transfer within the wick is also crucial.…”

Vampire bat's tongue-inspired superhydrophilic flexible origami channel for directional and spontaneous liquid manipulation

“…Efficient liquid manipulating processes have been considered an indispensable factor for optimizing the current functional systems such as heterogeneous catalysis, 1,2 cooling systems, 3,4 and water electrolysis. 5,6 Although the pumping technique can achieve fast and controllable fluid distribution, the cost of energy and equipment should be further lowered to meet the requirements in developing and remote areas.…”

Growth Restriction of Copper Nanocones at the Microgroove’s Bottom and Adjacent Sidewall Regions of Finned Heat Sinks

“…In the past decades, controllable growth of copper nanostructures has attracted intensive interest due to their significant academic and commercial values, e.g., used for enhancing the efficiency of condensers, , boilers, , and electronic coolers, fabricating bioinspired superwettability surfaces for antidew, antifrosting and anti-icing, − creating superaerophobic electrodes for catalysis reduction of CO 2 and CO to liquid fuels, and used as current collectors and anodes for lithium batteries . As compared to these single-scale nanostructures, micro/nanoscale composite structures with more surface area available for high-efficiency heat transfer and chemical reactions theoretically are preferable.…”

“…As compared to these single-scale nanostructures, micro/nanoscale composite structures with more surface area available for high-efficiency heat transfer and chemical reactions theoretically are preferable. For example, copper microgroove structures, as-fabricated by a classical skiving technology, have been widely used as liquid coolers of high-power electronic chips based on the fluorinated liquid pool boiling or water flow boiling because of their low processing cost and superior cooling properties. − However, with the rapid development of digital economy and consequently sharp increase in the demands for computing power, the power of state-of-the-art electronic chips has reached 700 W, posing a huge challenge to electronic chips’ cooling in the confined space. Nowadays, to meet the chips’ cooling demands, the spacings of copper microgroove structures of finned heat sinks have been reduced to 0.4 and even 0.2 mm in certain extreme scenarios, which is the lower limit of skiving technology.…”