A parametric study on pool boiling heat transfer and critical heat flux on structured surfaces with artificial cavities

Benam, Behnam Parizad; Ahmadi, Vahid; Motezakker, Ahmad Reza; Saeidiharzand, Shaghayegh; Villanueva, Luis Guillermo; Park, Hyun Sun; Sadaghiani, Abdolali Khalili; Koşar, Ali

doi:10.1016/j.applthermaleng.2022.119841

Cited by 7 publications

(3 citation statements)

References 72 publications

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“…The size of the bubbles increases as the operating heat flux increases. [ 71,72 ] Hence, our results show that at low and medium heat flux, surfaces with smaller spot pitch (e.g., smaller bubble sizes such as on surface a04p06) exhibit the best performance, facilitating moderate lateral bubble coalescence that increases liquid supply toward superhydrophobic regions. However, as heat flux increases (i.e., high heat flux region), bubble size also increases, leading to the unwanted formation of a vapor blanket over the superhydrophilic regions that prevents the liquid supply, resulting in poor boiling performance (see Figure 6e and f).…”

Section: Resultsmentioning

confidence: 78%

“…It has been reported that as the operating heat flux increases, the bubble size and number of active nucleation sites also increase, and the interaction between them changes. [ 71,72 ] In the low heat flux region, the diameter of a bubble can be measured, whereas in medium and high heat flux the nucleation frequency and bubble coalescence is too high for accurate measurements. In the low heat flux region, the mean bubble departure diameter changed from ≈0.5 to 1.4 mm, when the spot pitch was increased from 0.6 to 3.0 mm on samples with a constant spot size of 0.4 mm.…”

Section: Resultsmentioning

confidence: 99%

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

Hadžić,

Može,

Zupančič

et al. 2023

Adv Funct Materials

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The rapid advancement of engineering systems has spurred the search for innovative thermal management solutions. Boiling, as a phase‐change heat transfer method, has shown promise in heat dissipation, but non‐functionalized surfaces struggle with increasing cooling demands. To improve heat dissipation efficiency across different heat loads, functionalized surfaces with tailored wettability have been proposed. Separately, superhydrophilic and superhydrophobic surfaces each offer benefits and drawbacks in boiling applications but combining them on a single “biphilic” surface simultaneously harnesses their advantages. In this study, laser‐functionalized copper surfaces with spatially tailored wettability are developed by combining two‐step laser texturing with a self‐assembled monolayer coating, while focus is placed on the impact of the size and pitch of superhydrophobic spots. The developed functionalized surfaces exhibit exceptional boiling performance with heat transfer coefficients up to 299 kW m−2 K−1, a 434% enhancement over untreated surfaces. Optimal ratios of superhydrophilic and superhydrophobic areas and optimal spot pitch are identified. Additionally, varying behavior at different heat flux levels is observed, emphasizing the importance of considering thermal loads when determining the optimal surface pattern. This advancement in performance, along with the rapid and cost‐effective functionalization process, represents a significant breakthrough for enhanced thermal management applications.

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Section: Resultsmentioning

confidence: 78%

Section: Resultsmentioning

confidence: 99%

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

Hadžić,

Može,

Zupančič

et al. 2023

Adv Funct Materials

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“…The performance of electronic equipment in data centre will be weaken if the temperature over the allowable ranges. Therefore, thermal management is a critical issue in realizing the sustainable development of green data centre [4][5][6]. In recent years, the vapor chamber (VC) has gained tremendous attention in heat dissipation of electric devices by gas-liquid phase change methods [7,8].…”

Section: Introductionmentioning

confidence: 99%

A visualization study of a confined vapor chamber with conical microstructure applied in data centres

Liu,

Qin,

Yang

et al. 2024

IOP Conf. Ser.: Earth Environ. Sci.

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With the development of the informatization technology, the scale of the data centre is expanding rapidly. The energy consumptions of the electronic equipment in the data centre are rising regularly, which lead to the thermal management becoming an argent issue to be settled. To realize the sustainable development of green data centre, the passive two-phase vapor chamber (VC) has turned into the focus of electronic cooling research. Constructing nucleation induced structures on the evaporation surface is an effective method to improve the performance of the vapor chamber. To address the problem of achieving enhanced boiling, a novel conical microstructure was designed in the vapor chamber with 50 mm height. The conical structure of 1 mm axial height was fabricated on the evaporation surface by computer numerical control (CNC) machining technology. A visualization experimental system was developed to investigate the effect of the conical microstructure on the two-phase behaviours, and the boiling heat transfer characteristics under different heating conditions (Q in = 35 W, 50 W, 65 W) in a confined vapor chamber. The high-speed camera was used to capture the bubble behaviours. Experimental results found that compared with the smooth surface, the integration of the conical structure increasing the number of bubble nucleation sites and the bubble departure frequency. The bubble growth period at stable heating stage is 162 ms shorter than initial heating stage on the evaporation surface with conical structure. The thermal resistance (R vc) of vapor chamber with conical structure is improved by 5.85% compared to the smooth one at Q in = 65 W, which indicate that the conical microstructure can enhance the boiling heat transfer performance. This study aims to provide a reference for the design of thermal management system for green data centre.

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Effect of mixed wettability surfaces on flow boiling heat transfer at subatmospheric pressures

Ahmadi,

Guler,

Celik

et al. 2024

Applied Thermal Engineering

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A parametric study on pool boiling heat transfer and critical heat flux on structured surfaces with artificial cavities

Cited by 7 publications

References 72 publications

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

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

A visualization study of a confined vapor chamber with conical microstructure applied in data centres

Effect of mixed wettability surfaces on flow boiling heat transfer at subatmospheric pressures

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