Effects of surface oxide layer on the impact dynamic behavior of molten aluminum droplets

Yang, Wenjie; Yang, Rui; Yao, Yina; Gao, Zishan; Zhang, Hui

doi:10.1063/5.0136117

Cited by 6 publications

(3 citation statements)

References 51 publications

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“…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. In addition, the oxide film on the surface of molten aluminum is also a layer of elastic solid film with mechanical strength, which can increase viscous dissipation in the dynamic process of molten droplets [58]. The flow of molten aluminum droplets on the cable end is inevitably affected by the increased viscous dissipation from oxide film, and thus the function of oxide film represents a kind of resisting action for dripping.…”

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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“…However, the non-Newtonian characteristics should not only affect the impact process, but also the post-impact behavior. 49 The coupling effect of shear-thinning and impact conditions in the post-impact phase, such as rebound or deposition of the droplet on the surface, needs to be further investigated.…”

Section: ■ Introductionmentioning

confidence: 99%

“…All of these works suggest that the shear-thinning property may alter the dynamic wetting process, possibly due to the different levels of viscous dissipation with varying viscosities. However, the non-Newtonian characteristics should not only affect the impact process, but also the post-impact behavior . The coupling effect of shear-thinning and impact conditions in the post-impact phase, such as rebound or deposition of the droplet on the surface, needs to be further investigated.…”

Section: Introductionmentioning

confidence: 99%

Study on the Bouncing Behaviors of a Non-Newtonian Fluid Droplet Impacting on a Hydrophobic Surface

et al. 2023

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The control of a droplet bouncing on a substrate is of great importance not only in academic research but also in practical applications. In this work, we focus on a particular type of non-Newtonian fluid known as shear-thinning fluid. The rebound behaviors of shear-thinning fluid droplets impinging on a hydrophobic surface (equilibrium contact angle θ eq ≈ 108°and contact angle hysteresis Δθ ≈ 20°) have been studied experimentally and numerically. The impact processes of Newtonian fluid droplets with various viscosities and non-Newtonian fluid droplets with dilute xanthan gum solutions were recorded by a high-speed imaging system under a range of Weber numbers (We) from 12 to 208. A numerical model of the droplet impact on the solid substrate was also constructed using a finite element scheme with the phase field method (PFM). The experimental results show that unlike the Newtonian fluid droplets where either partial rebound or deposition occurs, complete rebound behavior was observed for non-Newtonian fluid droplets under a certain range of We. Moreover, the minimum value of We required for complete rebound increases with xanthan concentration. The numerical simulations indicate that the shear-thinning property significantly affects the rebound behavior of the droplets. As the amount of xanthan increases, the high shear rate regions shift to the bottom of the droplet and the receding of the contact line accelerates. Once the high shear rate region appears only near the contact line, the droplet tends to fully rebound even on a hydrophobic surface. Through the impact maps of various droplets, we found that the maximum dimensionless height H max * of the droplet increases almost linearly with We as H max * ∼ αWe. In addition, a critical value H max, c * for the distinction between deposition and rebound for droplets on the hydrophobic surface has been theoretically derived. The prediction of the model shows good consistency with the experimental results.

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Impact Deposition of a Single Droplet of Low‐Melting‐Point Alloy as the Top Electrode for Organic Photovoltaics

Yu,

Kang,

Liu

et al. 2024

Small Methods

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Top electrodes of organic photovoltaics (OPVs) are usually thermally evaporated in the vacuum, which is non‐continuous and time‐consuming and has been the bottleneck for the OPV fabrication process. Printable top electrodes that are free of vacuum, high temperature, and solvents will make OPVs more attractive. Low‐melting‐point alloys (LMPAs) are promising candidates for printable OPV electrodes thanks to the merits of matching work functions, high electron conductivity, high environment stability, and no need for post‐treatment. Here, LMPA electrodes are directly deposited on OPVs by simply falling a single LMPA droplet onto the substrate. The LMPA droplet spreads to form a thin film with a smooth interface intimately contacting the substrate. The electrode area can be tailored by adjusting the droplet diameter or the Weber number, which is the ratio of inertia to surface tension. The interface morphology is mainly affected by the contact temperature. The degree of oxidation and charges on the droplet can also influence the electrode area and interface morphology. OPVs with droplet‐impacted LMPA electrodes exhibit power conversion efficiencies of up to 16.17%. This work demonstrates the potential of single‐droplet impact deposition as a simple method for printing OPV electrodes for scalable manufacturing.

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Effects of surface oxide layer on the impact dynamic behavior of molten aluminum droplets

Cited by 6 publications

References 51 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

Study on the Bouncing Behaviors of a Non-Newtonian Fluid Droplet Impacting on a Hydrophobic Surface

Impact Deposition of a Single Droplet of Low‐Melting‐Point Alloy as the Top Electrode for Organic Photovoltaics

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