Between no slip and free slip: A new boundary condition for the surface hydrodynamics of a molten metal

Patouillet, Kévin; Davoust, Laurent

doi:10.1016/j.ces.2020.116328

Cited by 6 publications

(3 citation statements)

References 46 publications

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“…The molten aluminum surface will be inevitably covered by a layer of oxide film in the air. Some researchers revealed that the oxide film on the surface of molten aluminum has a highly viscous nature and shear-thinning behavior [56,57]. The shear rate is small when the arc spot does not act on the molten aluminum droplets, and the viscous force is large due to the shear-thinning property.…”

Section: The Mechanism Of Large Droplets Dripping During Arcing Of Hc0mentioning

confidence: 99%

Study on arc duration and erosion characteristics of cable electrodes in AC series circuits

Gao

Yang

et al. 2023

J. Phys. D: Appl. Phys.

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Arc duration and erosion characteristics of cables are closely related to electrical fire hazards. In this study, the arc duration and arc erosion characteristics of copper and aluminum core cables were explored. The main erosion modes of copper core cable with mica insulation (HC0) and aluminum core cable with PI insulation (HA0) were determined. Results show that several large molten droplets with diameters of 5±0.5mm would drip down from the molten pool on the cable end during arcing of HC0, but the molten droplets are adhered to the molten pool and do not drip down during arcing of HA0. We concluded that the differences in melting energy and oxide film between copper and aluminum are the main reasons for this phenomenon. Besides, the molten pool can be formed on the cable end as the insulation is heatproof, which plays a vital role in prolonging the arc duration of cables. The arc duration of cables with heatproof insulation is longer than those with common insulation. This means that the cables with heatproof insulation have higher fire hazards from the perspective of arc duration. To further understand the influence of molten pools on arc duration, an arc duration model was developed based on energy balance, which is beneficial in determining the arc duration of cables with heatproof insulation in electrical fire accident investigation.

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Section: The Mechanism Of Large Droplets Dripping During Arcing Of Hc0mentioning

confidence: 99%

Study on arc duration and erosion characteristics of cable electrodes in AC series circuits

Gao

Yang

et al. 2023

J. Phys. D: Appl. Phys.

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“…In general, the textbook assumption of a no-slip boundary will result in it being more difficult to drive the flow of fluids as the channel size decreases to the nanoscale, especially for highly viscous liquids (e.g., metallic glass in the supercooled liquid region); the no-slip boundary-induced drag resistance at the nanoscale will even far exceed the influence of the surface tension effect. , Therefore, the enabled rapid transport of fluids in nanochannels by breaking down the no-slip boundary − has attracted a great deal of attention in many fields, such as micro- and nanofluidics, ,− nanomedicine, , water purification, energy storage and conversion, , and nanofabrication. ,− The evidence of boundary slip has been reported in the fast flow of water through carbon nanotubes − and the flow of solvents and polymer melts , past solids. The degree of slip is intrinsically determined by the interaction between fluids and the wall and closely related to the nanochannel size, surface roughness, − viscosity of fluids, ,, surface structure and ordering, , etc.…”

Section: Introductionmentioning

confidence: 99%

Observation of a Large Slip Effect in the Nanoscale Flow of Highly Viscous Supercooled Liquid Metals

Xiang

Liu

2023

Langmuir

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Understanding and controlling the flow of materials confined in channels play important roles in science and engineering. The general no-slip boundary condition will result in it being more challenging to drive the flow as the channel size decreases to the nanoscale, especially for highly viscous liquids. Here, we report the observation of a large boundary slip in the nanoscale flow of highly viscous supercooled liquid metals (with viscosities of ≲10 8 Pa s), enabled by the hydrophobic treatment of smooth nanochannels. The slip length significantly depends on the pressure, which can be rationalized by the shear-dependent viscosity. Our findings provide not only new insights into the field of nanofluidics but also a practical technique for resolving the challenge in the net formation of highly viscous supercooled liquid metals at the nanoscale.

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“…And yet, it seems prior to avoid or to predict the phenomena related to gas entrapment during mold filling, 8 especially if the ultimate purpose is to improve the reliability of casting processes. Indeed, the oxide film continuously formed at the surface of molten alloy can be encapsulated, and further dragged away into the bulk under the effect of surface agitation induced from modified hydrodynamics 9,10 . This ultimately leads to the emergence of structural defects which can have serious consequences on the quality and the fatigue life of cast parts 11 .…”

Section: Introductionmentioning

confidence: 99%

Deal–Grove model revisited for a new insight into the oxidation of molten aluminum alloy: The A356 alloy, as a model system

2021

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Oxidation of A356 aluminum alloy at molten state is investigated from thermogravimetric analyses. Linear kinetics followed by unexpected logarithmic kinetics is observed during the oxidation process. Scanning electron microscopy imaging coupled with wavelength‐dispersive X‐ray spectroscopy analyses reveal a heterogeneous oxide layer composed of spinel (MgAl2O4) embedded in a nonoxidized alloy matrix. Nonlinear diffusion of magnesium through the heterogeneous oxide layer is the key mechanism proposed to explain the logarithmic kinetics. The growth of spinel phase causes a growing complexification of the aluminum network through which magnesium is diffusing. To model the magnesium transport through the oxide layer, an effective diffusion coefficient, build from the pioneering approach developed by Davies et al. (Davies, D., Evans, U. & Agar, J. (1954) Proc. Roy. Soc. London. A., 225, 443), is introduced in the Deal–Grove model.

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Between no slip and free slip: A new boundary condition for the surface hydrodynamics of a molten metal

Cited by 6 publications

References 46 publications

Study on arc duration and erosion characteristics of cable electrodes in AC series circuits

Study on arc duration and erosion characteristics of cable electrodes in AC series circuits

Observation of a Large Slip Effect in the Nanoscale Flow of Highly Viscous Supercooled Liquid Metals

Deal–Grove model revisited for a new insight into the oxidation of molten aluminum alloy: The A356 alloy, as a model system

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