3-D MHD Modeling of Internal Fault Arc in a Closed Container

Abstract

The phenomenon of an internal fault arc in a closed container has been investigated in a magnetohydrodynamic method, which simulates the arcing process ignited between two rod electrodes in air with ac current, including the distributions of temperature and pressure. Particularly, the pressure rises due to the fault arc at different locations within the container are calculated. More significant is that the fraction <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">${\rm k}_{\rm p}$</tex></formula> of electric arc energy leading to pressure rise, which is known as thermal transfer coefficient and obtained according to the experimental date before, can be determined by using the simulation method. Compared with the net emission coefficients radiation model, the semiempirical radiation model is more suitable to the pressure calculation with the re-absorption contributing to the pressure rise considered. The influence of different starting temperatures of the reabsorption layer in the semiempirical radiation model on the pressure rise is focused on. It is found that the radiation model with 0.7 <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$&lt; \alpha &lt; $</tex></formula> 0.83 is recommended and attempted in the pressure calculation of fault arcs, where <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$\alpha$</tex></formula> is an adjusted parameter about the starting temperature of the reabsorption layer. The simulation results of the pressure rise, arc voltage, arc power, and <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">${\rm k}_{\rm p}$</tex></formula> in the container agree with the experiments.