Development of Method for Estimating Long Gap Free Arc Column Path Using Image Processing Technique

Tanaka, Shin‐ichi; Sunabe, Kinya; Goda, Yutaka

doi:10.1541/ieejpes1990.121.4_481

Cited by 7 publications

(6 citation statements)

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“…Using a method developed previously by the authors [16], image data acquired by high-speed video cameras were processed to estimate a 3D arc path, so that the changeable arc length and expansion could be analyzed. In addition, the average internal field (voltage gradient) of the arc column was calculated by dividing the arc voltage by the arc column length.…”

Section: Methodsmentioning

confidence: 99%

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Internal voltage gradient and behavior of column on long‐gap DC free arc

Tanaka

Sunabe

Goda

2003

Electrical Engineering Japan

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SUMMARYThe internal voltage gradient and behavior of column on long-gap DC free arcs were analyzed quantitatively. In the analysis, an image processing technique developed by us was applied to the images shot from two orthogonal views by two high-speed video cameras to estimate the three-dimensional arc column paths. Objective free arcs were ignited between the rod electrodes with the current in the range of 100 to 2000A and the gap in the range of 1.6 to 3.2 m. In addition, some of the objective free arcs were placed in the external magnetic field brought about by a large coil. As a result, macroscopic changes with time in terms of the arc voltage gradient along the column path, the ratio of the arc column length to the gap length, and the distance from the center axis between the electrodes to the farthest point were derived. All average characteristics were shown as the experimental equations. In addition, the effect of the external magnetic field on the macroscopic velocity of the expansion was studied.

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Section: Methodsmentioning

confidence: 99%

“…The authors previously proposed a method for arc path estimation [16] employing a new extraction scheme to improve the effectiveness of image data processing. In the proposed method, two images of the arc column obtained by projection in orthogonal directions are used as input data, and the arc path is then estimated in three dimensions.…”

Section: Introductionmentioning

confidence: 99%

Internal voltage gradient and behavior of column on long‐gap DC free arc

Tanaka

Sunabe

Goda

2003

Electrical Engineering Japan

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“…The gap length, that is, the height of the solution domain, is selected as the same value as found in Tanaka et al (2001), i.e., 0.6 m in modeling and can be adjusted under different conditions. Figure 10A shows the spatial distribution of the lightning LCC arc channel in the current amplitude of 400 A and an airflow speed of 5 m/s in the +x direction.…”

Section: Different Speeds Of the Aerodynamic Flowmentioning

confidence: 99%

“…The normalized length of the arc column is defined as the ratio of the effective channel length to gap length. Tanaka et al used the highspeed imaging technique with a reconstruction algorithm (Tanaka et al, 2001) and found that these two time-dependent parameters manifest a noteworthy pattern with a certain boundary after arc ignition. The mean expansion radius enlarges from 0.11 m to 0.28 m, and the normalized length ranged between 1.5 and 2 when the arc current increases from 100 A to 2000 A (Tanaka et al, 2003).…”

Section: Introductionmentioning

confidence: 99%

Influence of the aerodynamic flow on the dynamic characteristics of a lightning sweeping arc

Xiao

Liu²

2023

Front. Astron. Space Sci.

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Lightning arc attachments during swept strokes are key information in the lightning protection design of fast-moving aircraft, wind turbines, rockets, etc. However, numerical modeling has not achieved success to predict the movement of lightning sweeping arcs due to the limited understanding of the complex multi-physics convolution in the arc fluid at present. This work builds a dynamic magneto-hydrodynamic (MHD) arc model based on the setup in the laboratory simulation of the lightning continuing current and couples the electric–magnetic–thermal–force processes to get insights into the lightning arc dynamics. The MHD theory and Newton’s second law of motion are also incorporated to describe the movement of arc segments in the conditions of aerodynamic flows with different intensities. Results show that, at the center region of the arc, the electromagnetic force, thermal buoyancy, and aerodynamic force are competitive, and all are determiners in predicting the arc displacement. In contrast, at the root region of the arc, the electromagnetic force dominates the arc movement with a flow speed under 10 m/s, while aerodynamic force takes the dominant role when the flow speed exceeds 50 m/s. The arc sweeping distance expands from 0.02 to 1.01 m as the aerodynamic flow increases from 5 to 200 m/s. Meanwhile, when increasing the pitch angle of the arc-connected surface, the arc root becomes more attached to the surface and the sweeping distance is predicted to get reduced. The conclusions offer references to construct a numerical model and predict the complex arc movement during lightning sweeping strokes.

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“…Instabilities of an arc plasma have been the subject of few investigations, even less with analytic approaches. Tanaka et al [9] consider those instabilities as a result of an interaction between magnetic forces and plasma movement. One well-known mechanism is a variation in the transverse component of Laplace force which results in fluctuations on axial velocity leading to classical sausage instabilities [10,11].…”

Section: Ideal Arc Deformation Modelmentioning

confidence: 99%

MHD modeling of rotating arc under restrike mode in ‘Kvaerner-type’ torch: II. Dynamics and stability at 20 bar pressure

Gueye¹,

Cressault²,

Rohani³

et al. 2019

J. Phys. D: Appl. Phys.

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This paper focuses on the 3D MHD modeling of a very high-pressure (20 bar) arc plasma at industrial level; the torch is a 'Kvaerner-type' one, made of two concentric graphite electrodes and where spots are displaced with an external magnetic field. Different phenomenologies in arc movement were observed, ranging from a gliding arc on electrodes surfaces to hopping arc foots and notably impacting electrodes erosion and the overall efficiency in the plasma process. Besides those dynamics which are indebted to torch configuration, current and flow rates, arc stability is also investigated with a theoretical model based on an energy principle. This research work provides new insight on the dynamics and stability of the arc inside the Kvaerner-type torch along with an unprecedented understanding of the very high pressure arc under concentric-electrodes-configuration, highlighting strong deformations due to pressuredriven instabilities for the high power arc.

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Development of Method for Estimating Long Gap Free Arc Column Path Using Image Processing Technique

Cited by 7 publications

References 0 publications

Internal voltage gradient and behavior of column on long‐gap DC free arc

Internal voltage gradient and behavior of column on long‐gap DC free arc

Influence of the aerodynamic flow on the dynamic characteristics of a lightning sweeping arc

MHD modeling of rotating arc under restrike mode in ‘Kvaerner-type’ torch: II. Dynamics and stability at 20 bar pressure

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