Investigation of Nucleate Pool Boiling of Saturated Pure Liquids and Ethanol-Water Mixtures on Smooth and Laser-Textured Surfaces

Zakšek, Peter; Zupančič, Matevž; Gregorčič, Peter; Golobič, Iztok

doi:10.1080/15567265.2019.1689590

Cited by 42 publications

(37 citation statements)

References 41 publications

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“…In this context, Zupančič et al [62] have shown that surfaces with laser-induced multiscale -cavities enable enhanced and controlled saturated nucleate boiling performance. This was proven further by Gregorčič et al [46], who successfully used such surfaces for enhanced and controlled boiling heat transfer in a wide range of fluids (further discussed in Section 12.4.3), independent of their polarity or surface tension, as well as by the experiments by Zakšek et al [84], who demonstrated that this kind of surfaces enable controlled boiling also in binary liquid mixtures. All these results confirm that functionalization of the heating surfaces by multiscale -cavities can decrease the influence of the surface wettability on the key boiling heat transfer parameters and, consequently, leads to more stable heat transfer processes that are independent of (i) fluid properties, (ii) hydrocarbon contaminants and (iii) ionizing radiation.…”

Section: Fabrication Of Multiscale -Cavities By Laser Texturingmentioning

confidence: 83%

“…While maintaining the same pressure and gravity, a decrease in bubble diameter can also be achieved by lowering the fluid's surface tension, which can be achieved either by using a different type of fluid [46,82], by adding an additional miscible fluid with low surface tension [83][84][85] or by adding nanoparticles [86]. These techniques can be used to decrease the bubble size, even though this does not necessarily result in an enhanced heat transfer coefficient as the required wall superheat for the bubble nucleation might also increase.…”

Section: Bubble Growth and Departurementioning

confidence: 99%

“…12.9b) is a modification of the previous scanning strategy leading to multiscale µ-cavities. Gregorčič et al [46] used this approach to enhance boiling heat transfer for a diverse range of fluids, independent on their polarity or surface tension, while Zakšek et al [84] have shown that this approach enhances boiling parameters also for binary mixtures.…”

Section: Laser Texturing Of Two-dimensional Surfacesmentioning

confidence: 99%

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Laser Surface Engineering for Boiling Heat Transfer Applications

Zupančič

Gregorčič

2021

Materials With Extreme Wetting Properties

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Nucleate boiling is inseparably connected with our everyday life. It is not only utilized in simple tasks like cooking, but it is also important for applications on various scales, ranging from enormous nuclear power plants to miniature microelectronics. This widespread integration is the result of its ability for effective heat transfer at low temperature differences between the heated surface and the surrounding fluid. The surface wettability undoubtedly influences the boiling heat transfer, but the observed behaviour cannot be explained without taking into account the surface topography and chemical modifications due to intense boiling processes. This chapter demonstrates how nucleate boiling enhancement can be achieved on surfaces with various wetting properties and specific micro/nano topographical features, fabricated using a straightforward, robust and scalable laser texturing approach. We discuss the basics of nucleate boiling and how it is affected by surface wettability; provide a fundamental background of laser surface engineering and its ability to achieve extreme wetting properties; and finally demonstrate the applicability of the laser-textured surfaces in enhancing and controlling nucleate pool boiling of different fluids. We show how laser surface engineering decreases the wettability effects on the key boiling parameters andin this wayensures more stable heat transfer performance.

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Section: Fabrication Of Multiscale -Cavities By Laser Texturingmentioning

confidence: 83%

Section: Bubble Growth and Departurementioning

confidence: 99%

Section: Laser Texturing Of Two-dimensional Surfacesmentioning

confidence: 99%

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Laser Surface Engineering for Boiling Heat Transfer Applications

Zupančič

Gregorčič

2021

Materials With Extreme Wetting Properties

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“…Most of the laser micro‐texturing studies have investigated the ablation of selected material to fabricate micro/nanoscale features for diverse applications. For example, the group of Peter Gregorčiča recently used the laser‐texturing process to produce micro‐channels and multiscale microcavities for enhancement heat transfer 17,18 …”

Section: Introductionmentioning

confidence: 99%

Wettability modification of zirconia by laser surface texturing and silanization

Jing

Yang

et al. 2020

Int J Applied Ceramic Tech

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This paper presents the modification of wettability by nanosecond laser surface textured followed by silanization to fabricate the superhydrophobic zirconia surface. Surface modification by varying the pitch between channels leads to micro‐channel and micro‐grid pattern with different surface roughness. The generated morphological and metallurgical modifications of the surface are measured by scanning electron microscopy (SEM) and X‐ray photoelectron spectroscopy (XPS). Numerous micro‐pits and cracks in the laser‐treated areas can be observed from SEM, which indicates crack propagation dominating the process of laser ablation of zirconia. The surface is superhydrophilic with laser‐texturing instantly, whose wettability is modified over time. By analyzing the XPS, carbon content, especially C‐C (H) groups, is important for the time‐dependent wettability. The hydrophobicity of all laser‐textured surfaces is improved after silanization. Laser texturing with smaller pitch (50 μm and 70 μm) leads to superhydrophobic surfaces after silanization, which may be due to the modification of physicochemical properties of substrate by very rapid local heating and cooling on the thick surface layer. Overall, the investigations indicate that wettability modifications can be attributed to the surface's microstructure, which depend on laser processing parameters, and chemical composition, especially in terms of −CF3, −CF2, and C‐C (H).

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“…Although some methods, such as immersion cooling [5,6] using nucleate boiling [7][8][9][10], can provide extremely high cooling performance, their integration into the cooled system is often difficult and expensive, making them less suitable for the consumer market. Heat pipes (HPs), on the other hand, still utilize the intense phase-change heat transfer processes, but in a closed package, making them very convenient for a variety of applications [11].…”

Section: Introductionmentioning

confidence: 99%

Experimental and numerical heat transfer analysis of heat-pipe-based CPU coolers and performance optimization methodology

Može

Nemanič

Poredoš

2020

Applied Thermal Engineering

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This paper presents an experimental and numerical heat transfer analysis of heat-pipe-based CPU coolers and a performance optimization methodology. The first part of the study focuses on the performance of two commercial HP-based CPU coolers under inclination angles of 0°, 90° and 180°. The results show that the 90° orientation provides the best thermal performance. The influence of heat pipe orientation on the performance of the entire system is obscured due to the much higher thermal resistance on the air-side of the cooler. A fourfold increase in air volumetric flow rate has only a minor effect on the cooling performance enhancement with a reduction of the thermal resistance from 0.11 K W-1 to 0.074 K W-1 at the highest heating power. In the second part of the study, heat transfer numerical simulations of the finned part of a cooler were performed and validated using experimental results. The output of the simulation is a 2-D temperature field, which is used as an input for the optimization methodology based on fin effectiveness and fin efficiency. Optimizing the fin geometry by removing unnecessary material yielded a 23% increase of the fin efficiency and decreased the weight of a fin by approx. 30%, proving the usefulness of the proposed methodology, which helps reduce costs, weight and development time of finned HP-based coolers.

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Investigation of Nucleate Pool Boiling of Saturated Pure Liquids and Ethanol-Water Mixtures on Smooth and Laser-Textured Surfaces

Cited by 42 publications

References 41 publications

Laser Surface Engineering for Boiling Heat Transfer Applications

Laser Surface Engineering for Boiling Heat Transfer Applications

Wettability modification of zirconia by laser surface texturing and silanization

Experimental and numerical heat transfer analysis of heat-pipe-based CPU coolers and performance optimization methodology

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