A hydrodynamic model for electrical arc modelling is used to study the interaction between the electrical arc and the sidewall in a low-voltage circuit breaker. The interaction model is based on an energy balance at the boundary. Comparisons of pressure, arc voltage and ablated mass between computations and experiments validate the model. The results confirm that the main mechanism at the sidewall is the photo-ablation. The model shows that, very rapidly, plastic vapours replace the air in the circuit breaker and are responsible for a residual conduction in the arc initiation region.

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A hydrodynamic model for electrical arc modelling, which takes into account Joule heating, radiation, Lorentz forces, arc - wall interactions and real-gas effects, was applied to study high-, medium- and low-voltage circuit breakers. The first industrial application deals with a high-voltage puffer circuit breaker. Ablation of the nozzle material in this kind of circuit breaker has been studied with the model. The second industrial application presents an self-blast medium-voltage circuit breaker, based on the combination of thermal expansion and the arc-rotation principle. The temperature between the contacts just after the current zero has been evaluated experimentally and numerically. The comparison between these results is discussed. Lastly, the arc commutation in a low-voltage circuit breaker has been simulated. The results show that, in this type of experimental set-up, the interaction among the electrical arc, the flow and the Lorentz force is preponderant.