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

Abstract

AbstractEnhanced 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).