Influence of surface roughness on the supercooling degree: Case of selected water/ethanol solutions frozen on aluminium surfaces

Faucheux, Matthieu; Müller, Guillaume; Havet, Michel; Le‐Bail, Alain

doi:10.1016/j.ijrefrig.2006.01.002

Cited by 48 publications

(23 citation statements)

References 4 publications

(1 reference statement)

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“…For pure water, the nucleation is homogeneous [10] and the critical size [11] of water molecule clusters determines whether or not the cluster can grow to ice. In DSC, the internal surface of sample holder provides a surface for heterogeneous nucleation [12], highly depending on the wet angle of water.…”

Section: Resultsmentioning

confidence: 99%

Reduction of supercooling of water by TiO₂ nanoparticles as observed using differential scanning calorimeter

Chen

Jia

et al. 2011

Journal of Experimental Nanoscience

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Aqueous dispersions of Titania nanoparticles were cooled using differential scanning calorimetry (DSC). The nanoparticles reduce the supercooling of water by acceleration of nucleation. The experimental results demonstrated the important role in water crystallisation by the internal surface of the sample holder, and that stable nanofluids are required for the measurements to investigate the effect of nanoparticles on freezing. But for dispersions at low concentrations, such as 0.05 wt% and 0.1 wt%, the starting temperatures of freezing were found to be unusual at the cooling rates of 3 C/min and 4.5 C/min, namely they were even lower than that of the deionised (DI) water. It is found that surface controlled nucleation (SCN) is dominant at low cooling rates, while volumetric controlled nucleation (VCN) is dominant at high cooling rates.

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Section: Resultsmentioning

confidence: 99%

Reduction of supercooling of water by TiO₂ nanoparticles as observed using differential scanning calorimeter

Chen

Jia

et al. 2011

Journal of Experimental Nanoscience

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“…Instead of taking temperature difference between two maximums, DT is defined as the difference between the highest temperature in melting peak and the lowest temperature in solidifying peak. The super-cooling of microsized particles of phase change materials can be reduced by adding nucleating agent to reduce nucleation barrier [3][4][5][6][7][8] or controlling working conditions such as degree of over-heating and cooling rates [9,10]. However there is no effective way to reduce super-cooling of metallic nanoparticles, which cannot be doped readily with non-molten impurities due to small size and lack of material with matching structure.…”

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confidence: 99%

Controlling supercooling of encapsulated phase change nanoparticles for enhanced heat transfer

Yan

et al. 2011

Chemical Physics Letters

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“…58 µm for v=5 m/min. Based on a review of selected literature presented in the bibliography concerned with the issues of heat transfer intensification involving the working medium phase, the highest values (R a ) of sample surfaces used for tests were recorded as follows: 10 µm in [10], 10.5 µm in [12], 13.04 µm in [9] or 13.33 µm in [11]. As a consequence of applying vibration-laser treatment, the R a values are significantly higher and should have a significant impact on the improvement of heat dissipation properties.…”

Section: Profilometric Evaluationmentioning

confidence: 99%

“…The techniques are used to modify the metal surface by means of, among others, the following types of reaction: a) chemical -pits obtained through chemical reactions, [3], [8], b) thermal -sintering of metal particles, [4], c) mechanical -creating microribs on the surface, application of finely cut grooves, making valleys, holes, projections or sand blasting, shot-peening, treatment with abrasive paper or abrasive compounds [7], [8], [9], [11], [12], d) laser beam -(making microholes by means of a laser beam, laser melting) and electrical discharge machining (EDM) [5], [6], [10]. The presented paper discusses the preliminary results of experimental research on the new technology of enhancing the roughness of metal elements.…”

Section: Introductionmentioning

confidence: 99%

An Evaluation of the use of Laser-Vibration Melting to Increase the Surface Roughness of Metal Objects

Grabas¹

2015

Archives of Metallurgy and Materials

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This paper presents preliminary, experimental results of a new, hybrid method of increasing the surface roughness of metal objects. In this new approach, metal objects are melted with a mobile laser beam while they are being rotated. A vibration generator provides circular vibrations with an amplitude of 3 mm, and the vibration plane is perpendicular to the moving laser beam. The melting tests were performed using flat carbon steel samples at a predetermined frequency of circular vibrations. The effects of laser power and laser beam scanning velocity on the melted shapes were studied. All laser melting procedures were performed at a vibration frequency of 105 Hz. The melted samples were subjected to microscopic evaluation and the R a parameter, which characterises mean roughness, was measured using a profilometer. Melting metal samples with physically smooth surfaces (R a = 0.21 µm) resulted in surface structures of varied roughness values, with R a ranging from 5 µm to approximately 58 µm. The studies were undertaken to employ this technology for the purpose of passive heat exchange intensification of heating surfaces in practical applications.Keywords: laser melting, surface roughness, laser treatment, vibration, nucleate boiling W artykule zaprezentowano wstępne wyniki eksperymentalne nowej hybrydowej metody zwiększania chropowatości powierzchni elementów metalowych. W metodzie tej wykorzystuje się przetapianie ruchomą wiązką laserową elementów metalowych poddanych równocześnie wibracji kołowej. Generator drgań wytwarza wibrację kołową o amplitudzie 3 mm, a płaszczyzna wibracji jest prostopadła do osi przemieszczającej się wiązki laserowej. Próbom przetapiania przy ustalonej częstotliwości wibracji kołowej poddano płaskie próbki ze stali węglowej. Badano wpływ mocy laserowej oraz prędkości skanowania wiązki laserowej na kształt przetopień. Wszystkie przetopienia laserowe wykonywano przy częstotliwości wibracji f = 105 Hz. Otrzymane przetopy poddane zostały obserwacjom mikroskopowym oraz pomiarom profilometrycznym parametru R a charakteryzującego średnią chropowatość. W wyniku przetapiania technicznie gładkich powierzchni próbek metalowych (R a = 0,21 µm), uzyskano struktury o zróżnicowanych chropowatościach, dla których R a mieścił się w przedziale od ok. 5 µm do ok. 58 µm. Badania prowadzono pod kątem potencjalnych możliwości stosowania tej technologii do pasywnej intensyfikacji wymiany ciepła powierzchni płyt grzewczych.

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Influence of surface roughness on the supercooling degree: Case of selected water/ethanol solutions frozen on aluminium surfaces

Cited by 48 publications

References 4 publications

Reduction of supercooling of water by TiO₂ nanoparticles as observed using differential scanning calorimeter

Reduction of supercooling of water by TiO₂ nanoparticles as observed using differential scanning calorimeter

Controlling supercooling of encapsulated phase change nanoparticles for enhanced heat transfer

An Evaluation of the use of Laser-Vibration Melting to Increase the Surface Roughness of Metal Objects

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Influence of surface roughness on the supercooling degree: Case of selected water/ethanol solutions frozen on aluminium surfaces

Cited by 48 publications

References 4 publications

Reduction of supercooling of water by TiO2 nanoparticles as observed using differential scanning calorimeter

Reduction of supercooling of water by TiO2 nanoparticles as observed using differential scanning calorimeter

Controlling supercooling of encapsulated phase change nanoparticles for enhanced heat transfer

An Evaluation of the use of Laser-Vibration Melting to Increase the Surface Roughness of Metal Objects

Contact Info

Product

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Reduction of supercooling of water by TiO₂ nanoparticles as observed using differential scanning calorimeter

Reduction of supercooling of water by TiO₂ nanoparticles as observed using differential scanning calorimeter