Nanoparticle-Assisted Pool Boiling Heat Transfer on Micro-Pin-Fin Surfaces

Abstract

Boiling heat transfer intensification is of significant relevance to energy conversion and various cooling processes. This study aimed to enhance the saturated pool boiling of FC-72 (a dielectric liquid) by surface modifications and explore mechanisms of the enhancement. Specifically, circular and square micro pin fins were fabricated on silicon surfaces by dry etching and then copper nanoparticles were deposited on the micro-pin-fin surfaces by electrostatic deposition. Experimental results indicated that compared with a smooth surface, the micro pin fins increased the heat transfer coefficient and the critical heat flux by more than 200 and 65–83%, respectively, which were further enhanced by the nanoparticles up to 24% and more than 20%, respectively. Correspondingly, the enhancement mechanism was carefully explored by high-speed bubble visualizations, surface wickability measurements, and model analysis. It was quantitatively found that small bubble departure diameters with high bubble departure frequencies promoted high heat transfer coefficients. The wickability, which characterizes the ability of a liquid to rewet a surface, played an important role in determining the critical heat flux, but further analyses indicated that evaporation beneath bubbles was also essential and competition between the wicking and the evaporation finally triggered the critical heat flux.

Superbiphilic Laser‐Microengineered Surfaces with A Self‐Assembled Monolayer Coating for Exceptional Boiling Performance

“…Although boiling heat transfer is one of the most intense heat transfer mechanisms, researchers in this field have extensively investigated numerous types of methods in the last few decades [8,9] to further improve the boiling performance. Studies range from enhancements based on boiling fluid modification, [9,10] such as with the addition of nanoparticles (i.e., nanofluids) [11,12] or with mixtures of different surface tensions, [13,14] to studies focusing on surface modification, [15,16] with an emphasis on changing the surface topography [17,18] and morphology [19,20] alongside with its wetting behavior. [21,22] In recent years, various technologies have been explored to tailor the surface topography and morphology to improve boiling performance.…”

Heat Transfer Characteristics of Pool Boiling with Scalable Plasma-Sprayed Aluminum Coatings

“…Heat enhancement in pool boiling is required in various industrial and household applications like thermal power generation, space industry, refrigeration, air conditioning, chemical processing industry, electronic device cooling, and several others. Over the last few decades, substantial research works have investigated various surface modification strategies for improving pool boiling thermal performance. − …”

Influence of Surface Wettability on Bubble Formation and Motion

“…Pool boiling is a widely used cooling technique in high heat flux applications such as integrated microelectronic devices, nuclear reactors, and space equipment. , To meet the increasing heat dissipation demands, various surface patterns have been designed and investigated to enhance pool boiling heat transfer, such as micro-pin-fin, pillar, micro/nano tube, , nanowire, and microporous architecture . Results indicate that surface wettability has significant influence on pool boiling because it affects bubble behaviors and liquid wetting state on the heating surface. − Previous studies have reported that hydrophobic surfaces promote early onset of nucleate boiling (ONB), although bubbles tend to stay on hydrophobic surfaces, which leads to lower critical heat flux (CHF).…”

“…Pool boiling is a widely used cooling technique in high heat flux applications such as integrated microelectronic devices, nuclear reactors, and space equipment. , To meet the increasing heat dissipation demands, various surface patterns have been designed and investigated to enhance pool boiling heat transfer, such as micro-pin-fin, pillar, micro/nano tube, , nanowire, and microporous architecture . Results indicate that surface wettability has significant influence on pool boiling because it affects bubble behaviors and liquid wetting state on the heating surface. − Previous studies have reported that hydrophobic surfaces promote early onset of nucleate boiling (ONB), although bubbles tend to stay on hydrophobic surfaces, which leads to lower critical heat flux (CHF). On the contrary, hydrophilic surfaces delay the CHF, but they need larger superheat to initiate nucleate boiling. ,, …”