Pool Boiling Inversion and Hysteresis with Femtosecond Laser Processed 304 Stainless Steel Surfaces for Heat Transfer Enhancement

Costa-Greger, Justin; Tsubaki, Alfred; Gerdes, Josh; Anderson, Mark; Zuhlke, Craig; Alexander, Dennis R.; Shield, J. E.; Gogos, George

doi:10.1109/itherm45881.2020.9190948

Cited by 8 publications

(1 citation statement)

References 24 publications

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“…A series of studies by Kruse et al, Costa-Greger et al and Gogos et al [32][33][34][35][36] focused on femtosecond laser texturing of surfaces to enhance boiling heat transfer. They achieved an enhancement of both the HTC and the CHF on stainless steel and copper surface.…”

Section: Laser-textured Surfaces For Boiling Enhancementmentioning

confidence: 99%

Nanosecond Laser-Textured Copper Surfaces Hydrophobized with Self-Assembled Monolayers for Enhanced Pool Boiling Heat Transfer

et al. 2022

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Increased cooling requirements of many compact systems involving high heat fluxes demand the development of high-performance cooling techniques including immersion cooling utilizing pool boiling. This study presents the functionalization of copper surfaces to create interfaces for enhanced pool boiling heat transfer. Three types of surface structures including a crosshatch pattern, shallow channels and deep channels were developed using nanosecond laser texturing to modify the surface micro- and nanomorphology. Each type of surface structure was tested in the as-prepared superhydrophilic state and superhydrophobic state following hydrophobization, achieved through the application of a nanoscale self-assembled monolayer of a fluorinated silane. Boiling performance evaluation was conducted through three consecutive runs under saturated conditions at atmospheric pressure utilizing water as the coolant. All functionalized surfaces exhibited enhanced boiling heat transfer performance in comparison with an untreated reference. The highest critical heat flux of 1697 kW m−2 was achieved on the hydrophobized surface with shallow channels. The highest heat transfer coefficient of 291.4 kW m−2 K−1 was recorded on the hydrophobized surface with deep channels at CHF incipience, which represents a 775% enhancement over the highest values recorded on the untreated reference. Surface microstructure was identified as the key reason for enhanced heat transfer parameters. Despite large differences in surface wettability, hydrophobized surfaces exhibited comparable (or even higher) CHF values in comparison with their hydrophilic counterparts, which are traditionally considered as more favorable for achieving high CHF values. A significant reduction in bubble departure diameter was observed on the hydrophobized surface with deep channels and is attributed to effective vapor entrapment, which is pointed out as a major contributing reason behind the observed extreme boiling heat transfer performance.

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Section: Laser-textured Surfaces For Boiling Enhancementmentioning

confidence: 99%

Nanosecond Laser-Textured Copper Surfaces Hydrophobized with Self-Assembled Monolayers for Enhanced Pool Boiling Heat Transfer

et al. 2022

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Three‐Tier Hierarchical Structures for Extreme Pool Boiling Heat Transfer Performance

et al. 2022

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The heat transfer coefficient (HTC, h) and critical heat flux (CHF, q″ CHF ) are two major parameters that quantify boiling performance. The HTC describes the efficiency of boiling heat transfer, defined as the ratio of heat flux (q″) to the wall superheat (ΔT w ), that is, h = q″/ΔT w . Here ΔT w is the temperature difference between the boiling surface and the saturated liquid. In the nucleate boiling regime, the heat flux increases with the wall superheat. However, when the heat flux is sufficiently high, excessive vapor bubbles nucleated on the boiling surface prevent the liquid from rewetting the surface and, in turn, form an insulating vapor film over the surface. This vapor film becomes a thermal barrier that leads to a drastic increase in wall superheat and burnout of a boiling system. This transition from nucleate boiling to film boiling is known as the boiling crisis, where the maximum heat flux is CHF. Enhancing CHF, therefore, can either enable larger safety margins or extend the operational heat flux range for boiling systems. [5] Recent efforts to enhance boiling heat transfer have focused on engineering the working fluid or surface properties. [6] In particular, engineering surface structures have received greater attention owing to the constraints on chemical compatibility or operational conditions which can limit the choice of the working fluid. Representative examples of surface structures that effectively enhance CHF are known to be hemi-wicking surfaces such as micropillars and nanowires. [7] These structures enhance CHF by harnessing thin-film evaporation around pillars and capillary-fed wicking through the structures. [8] Surfaces with microcavities, on the other hand, have shown improved HTC by trapping vapor embryos that promote nucleation. [9] Recently, a combination of microtube and micropillar structures referred to as tube-clusters in pillars (TIP), has shown the ability to tune the HTC and CHF by controlling bubble coalescence while maintaining capillary wicking. [10] Despite the controllability, achieving extreme enhancement of HTC and CHF simultaneously remains challenging due to the intrinsic tradeoff between HTC and CHF associated with nucleation-site density. For example, high nucleation-site density may increase HTC but decrease CHF because extensive bubble coalescence hinders the capillary wicking performance, while the reduced number of nucleation sites will limit the HTC enhancement.Boiling is an effective energy-transfer process with substantial utility in energy applications. Boiling performance is described mainly by the heat-transfer coefficient (HTC) and critical heat flux (CHF). Recent efforts for the simultaneous enhancement of HTC and CHF have been limited by an intrinsic trade-off between them-HTC enhancement requires high nucleation-site density, which can increase bubble coalescence resulting in limited CHF enhancement. In this work, this trade-off is overcome by designing three-tier hierarchical structures. The bubble coalescence is minimized to enhance the ...

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Achieving robust and enhanced pool boiling heat transfer using micro–nano multiscale structures

Wang

Jiang

et al. 2023

Applied Thermal Engineering

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Pool Boiling Inversion and Hysteresis with Femtosecond Laser Processed 304 Stainless Steel Surfaces for Heat Transfer Enhancement

Cited by 8 publications

References 24 publications

Nanosecond Laser-Textured Copper Surfaces Hydrophobized with Self-Assembled Monolayers for Enhanced Pool Boiling Heat Transfer

Nanosecond Laser-Textured Copper Surfaces Hydrophobized with Self-Assembled Monolayers for Enhanced Pool Boiling Heat Transfer

Three‐Tier Hierarchical Structures for Extreme Pool Boiling Heat Transfer Performance

Achieving robust and enhanced pool boiling heat transfer using micro–nano multiscale structures

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