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This article presents a comprehensive multiphase computational fluid dynamics model to simulate the arc heating process in the ladle. The results on temperature distribution, slag eye size, flow characteristics, and wall shear stress under three flow rate conditions are discussed. Validation of the results is carried out by comparing them with industrial measurements. The study highlights that when the flow rate increases by 100%, the temperature difference in the ladle decreases by 17.37%, while the slag eye‐opening and wall shear stress increase by 116.38% and 49.86%, respectively. The study emphasizes the details of model development and utilization of models to optimize the process. [ABSTRACT FROM AUTHOR]

Carbon nanomaterials are the major and fastest growing area of nanotechnology. Their exceptional properties find application in numerous sectors of the economy. However, their large-scale production with adequate quality is still an open problem. In the present work, the advances obtained in the development of the submerged arc discharge technology for the production of carbon nanostructures in the Nanosciences Group of CEADEN are presented. We also report the implementation of methods for the safety evaluation of the in vitro use of carbon nanostructures synthesized using this method. [ABSTRACT FROM AUTHOR]

In bushfire-prone regions, powerline faults, notably single line-to-ground (SLG) faults, are significant contributors to wildfires. In order to promptly mitigate conflagration risks and reduce fault currents from SLG faults, the resonant grounded (RG) technique is implemented. Nevertheless, the literature has not reported a comprehensive derivation of SLG faults using this grounding method. The dynamic phasors method is used in this study to extract fault current characteristics, which are subject to substantial variations under various operating conditions, including harmonics, fault impedance variations, and the compensation levels necessary for resonance. The behavior of fault currents resulting from SLG faults is analyzed in this work by first deriving the fault current under RG conditions, accounting for leakage parameters, and subsequently incorporating harmonic components. The simulation results unequivocally demonstrate that the fault current retains a residual component, even under ideal resonance conditions, and that the ground fault neutralizer does not suppress this residual fault current. The analysis presented indicates that it is imperative to exercise caution when selecting the resonant grounding approach. Further, this method can be employed to extract the remaining fault current component, which is not explicitly accounted for, in order to identify faulty feeders in nonlinear high impedance fault scenarios. • A detailed derivation process for the SLG fault current in an RGPDN. • An evidence about the presence of harmonics in the fault current during the fault. • The necessity of utilizing the RCC inverter for fault compensations. • Revealing different components of the fault current in an RGPDN. [ABSTRACT FROM AUTHOR]

A channel arc model (CAM) that predicts the temperature and the geometry of an electric arc from its voltage and impedance set‐points is presented. The core of the model is a nonlinear programming (NLP) formulation that minimizes the entropy production of a plasma column, the physical and electrical properties of which satisfy the Elenbaas–Heller equation and Ohm's law. The radiative properties of the plasma are approximated utilizing the net emission coefficient (NEC), and the NLP is solved using a global numerical solver. The effects of the voltage and impedance set‐points on the length of the electric arc are studied, and a linear formula that estimates the length of the arc in terms of its electrical set‐points is deducted. The length of various electric arcs is measured in a fully operative electric arc furnace (EAF), and the results are used to validate the proposed models. The errors in the predictions of the models are 0.5 and 0.4 cm. In comparison, the existing empirical and Bowman formulae estimate the length of the experimental arcs with errors of 2.1 and 2.6 cm. A simplified formula to estimate the temperature of an electric arc in terms of its electrical set‐points is also presented. [ABSTRACT FROM AUTHOR]

Throughout its lifetime, high-voltage circuit breaker (HVCB) contacts suffer from inevitable degradation processes, especially during the formation of electric arcs. Highly degraded contacts can reduce the current interruption capacity and increase the chances of operational faults, which might lead to considerable financial losses. Therefore, the use of efficient evaluating techniques is a key factor to achieve systems reliability. The dynamic resistance measurement (DRM) is a technique that can be used to evaluate the degradation level of HVCB' contacts. It stands out from the usual technique, static resistance measurement, by allowing the assessment of both the main contacts and the arcing contacts (ACs). Usually, the mean resistance or the area under the DRM curve is used to estimate the AC degradation. However, DRM is a non-standardised technique and there are no specified parameters to evaluate the real wear conditions. Therefore, an analysis of alternative parameters extractible from the DRM technique is presented in this study, such as amplitude and variance of the DRM curve. The results attest the possible use of more than one parameter for the continuous evaluation of HVCB ACs, characterising the DRM as a more complete and precise diagnosis tool.

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The motion of the gliding DC electric arc under the effect of magnetic field is investigated. The temperature distribution in the inside and the outside of the moving arc is computed. The temperature distribution for the fixed-spot arc is also obtained. It appears that the gas relative velocity inside the arc gives rise to heat convection, which has an impact on the arc motion. A practical analytical solution is derived using magneto gas dynamic equations in order to investigate the heat transfer occurring in the arc and its vicinity, to determine its characteristics, and to estimate its velocity when it is exposed to external and electrode-induced magnetic fields. Two methods are suggested: one for the free-burning arc and the other for arc burning between close surrounding walls. [ABSTRACT FROM AUTHOR]