Sustainable dropwise condensation enabled ultraefficient heat pipes

Abstract

Heat pipes play a critical role in determining the operations, safety, and energy efficiency of electronics. The main focus to improve the heat pipe performance is on the evaporator design or wicking structures. However, the intrinsic limitation comes from the condenser, which is fundamentally constrained by inefficient filmwise condensation (FWC). In this study, we successfully achieved a peak effective thermal conductivity (k eff ) of ~140 kW/(m•K) on widely used groove heat pipes by implementing sustianble dropwise condensation (DWC) and integrating with enhanced evaporator. To better understand the working mechanisms of the ultraefficient heat pipe, both the evaporator and condenser of the heat pipes have been modified accordingly. Our results show that up to 296% enhancements on the k eff can be achieved under various inclination angles by only inducing DWC in the condenser section. The drawback of temperature fluctuations induced by DWC in smooth heat pipes appears to be effectively solved using the grooves-wicking structure. Furthermore, by integrating the nanostructured evaporator, the k eff of the heat pipe can be boosted up to 517% compared to conventional groove heat pipes.This study, for the first time, demonstrates the huge potential of engineering both the condenser and evaporator simultaneously in developing ultraefficient heat pipes.

Droplet orthogonal impact on nonuniform wettability surfaces

“…In contrast, common‐day surfaces mostly exhibit spatially nonuniform wettability. Certain industrial and engineering technologies where these nonuniform wettability surfaces are used, include enhanced phase‐change heat transfer, 19–22 inkjet printing on heterogeneous surfaces, or solder droplet deposition on electronic circuits, which are inherently nonuniform. Furthermore, droplet impact on engineered surfaces is seen in emerging areas, such as droplet‐based electricity generators, 23 efficient direct cooling at ultra‐high solid temperature, 24 and so on.…”

Designing Versatile Superhydrophilic Structures via an Alginate-Based Hydrophilic Plasticene

“…Interfaces possessing special functions have emerged as a powerful platform for innovating materials and devices in both scientific research and modern technology [ 1 , 2 , 3 , 4 , 5 , 6 ]. The extreme interaction between fluids and a superwetting interface can facilitate a series of fluid-controlling processes such as liquid-repellency [ 7 , 8 ], fluid separation [ 9 ], gas extraction [ 10 ], etc.…”

Uniform and Persistent Jumping Detachment of Condensed Nanodroplets

“…On superhydrophobic surfaces like lotus leaves, coalescing microdroplets can spontaneously jump and detach, powered by the released liquid–gas surface energy, leading to a maximum residual droplet radius on a 100 μm scale. , For antifogging purposes, the jumping droplet strategy is employed by various wildlife, notably water striders, cicada, and mosquitos/flies, , to maintain movement flexibility, self-cleanliness, and visual clarity. In industrial contexts, efficient removal of condensed droplets helps reduce the thermal resistance of residual condensate, thereby enhancing heat transfer performance, , which is crucial in electronic devices’ thermal management and electric power production. − Jumping droplet strategy has shown great potential in such applications thanks to the minimized size of droplet detachment. − …”