Modelling of sparking contacts for hazardous area applications

Shekhar, Rajiv; Uber, Carsten

doi:10.1109/holm.2015.7355119

Cited by 2 publications

(6 citation statements)

References 5 publications

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“…A similar approach to Ref. [4,8] is taken, applying it to the recent dataset of Ref. [10] and adding a more detailed consideration of varying arc geometry.…”

Section: Empirical Discharge Modelmentioning

confidence: 99%

“…The quasi-static relationship between voltage (v), current (i d ) and length (l) in µm of the discharges takes the form of (1) [8].…”

Section: Voltage and Currentmentioning

confidence: 99%

“…for density ρ and velocity u. Additionally, conservation of momentum is given by the Navier-Stokes equations ∂ρu ∂t + ∇ · (ρuu) + ∇p = ∇ · τ + ρg (8) for pressure p and gravity vector g = [0 − 9.8 0] T . The viscous stress tensor τ is calculated from Newton's law…”

Section: Conservation Equationsmentioning

confidence: 99%

“…A similar approach to Ref. [4,8] is taken, applying it to the recent dataset of Ref. [10] An example of this data for one discharge event is shown in figure 2.…”

Section: Empirical Discharge Modelmentioning

confidence: 99%

“…In models of discharges in switching electrodes at high currents, the bulk of the plasma is often considered to be in LTE [7]. Quasi-static empirical models are also used for equilibrium arcs, and have shown some success in this application [8]. The radiation emitted by the discharge was also confirmed to comprise predominantly of atomic lines of cadmium [9].…”

Section: Introductionmentioning

confidence: 99%

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Numerical investigation of transient, low-power metal vapour discharges occurring in near limit ignitions of flammable gas

Shekhar¹,

Gortschakow²,

Großhans³

et al. 2018

J. Phys. D: Appl. Phys.

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This article presents an investigation of a transient (30 µs -5 ms) electrical discharge in metal vapour with low voltage (≤ 30 V) and current (≤ 200 mA), drawn between two separating electrodes. Discharges of this type are rarely studied, but are important in electrical explosion safety, as they can ignite flammable gasses. An empirical model is developed based on transient recordings of discharge voltages and currents and high speed broadband image data. The model is used for predicting the electrical waveforms and spatial power distribution of the discharge. The predicted electrical waveforms show good accuracy under various scenarios. To further investigate the underlying physics, the model is then incorporated into a simplified 3-D gas dynamics simulation including molecular diffusion, heat transfer and evaporation of metal from the electrode surface. The local thermodynamic equilibrium (LTE) assumption is next used to calculate electrical conductivity from the simulated temperature fields, which in turn is integrated to produce electrical resistance over time. This resistance is then compared to that implied by the voltage and current waveforms predicted by the empirical model. The comparison shows a significant discrepancy, yielding the important insight that the studied discharge very likely deviates strongly from LTE.

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“…A similar approach to Ref. [4,8] is taken, applying it to the recent dataset of Ref. [10] and adding a more detailed consideration of varying arc geometry.…”

Section: Empirical Discharge Modelmentioning

confidence: 99%

“…The quasi-static relationship between voltage (v), current (i d ) and length (l) in µm of the discharges takes the form of (1) [8].…”

Section: Voltage and Currentmentioning

confidence: 99%

Section: Conservation Equationsmentioning

confidence: 99%

“…A similar approach to Ref. [4,8] is taken, applying it to the recent dataset of Ref. [10] An example of this data for one discharge event is shown in figure 2.…”

Section: Empirical Discharge Modelmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Numerical investigation of transient, low-power metal vapour discharges occurring in near limit ignitions of flammable gas

Shekhar¹,

Gortschakow²,

Großhans³

et al. 2018

J. Phys. D: Appl. Phys.

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Ignition by Electrical Discharges

Markus

Essmann

Kummer

et al. 2017

Zeitschrift Für Physikalische Chemie

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The ignition of combustible/air mixtures by electrical discharges includes several physical and chemical processes. In process safety often the total available electrical energy is taken as a risk measure. However, to get a more detailed insight in the ignition process, also energy losses to the surrounding have to be considered. Additionally, for specific discharges not only the dissipation leading to thermal heating is of importance. Especially in the case of non-equilibrium plasma, a specific fractional amount of the discharge energy is used for electron impact dissociation, excitation, and ionization reactions, producing active radicals and ions during the discharge phase. While the electrical energy can be measured easily, it is difficult to determine energy losses. In this paper three different electrical discharges are examined experimentally and numerically to yield a better understanding of the ignition by electrical discharges.

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Modelling of sparking contacts for hazardous area applications

Cited by 2 publications

References 5 publications

Numerical investigation of transient, low-power metal vapour discharges occurring in near limit ignitions of flammable gas

Numerical investigation of transient, low-power metal vapour discharges occurring in near limit ignitions of flammable gas

Ignition by Electrical Discharges

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