french version

Modeling and simulation of the electrical arc discharge in porous in the case of HBC fuse

Scientific team : Rochette D. , Clain S.*
* LMA - CNRS UMR 6620 - Univ. Blaise Pascal - 24, Av. des Landais - F63177 AUBIERE CEDEX FRANCE

objectives

The study deals with to consider the fuse operation in the high breaking capacity fuses like a hot gas explosion in porous media while being based on gas dynamic. This approach calls upon the modeling of diphasic flows compressible gas-solid. The principal aspects of the problems to be treated are dependent :

Modeling and the numerical implementation by means of adapted methods as finite volume schemes makes it possible to obtain a better evaluation of the physical parameters characterizing the phenomenon and to better understand the silica sand influence.

Fuse operation phenomena. Fluid and silica sand evolution.

Purpose

An one-dimensional flow model based on the Euler equations in porous media, built on homogenized parameters, was carried out. Mechanical interaction is represented by the Brinkmann-Darcy-Forchheimer model and the thermal transfers are evaluated by the phenomena of conduction and convection. This model allows to evaluate the evolution of the fluid (pressure, temperature, velocity) in porous media during the fuse operation.

The fuse operation being compared to an explosion (great gradients of temperature and pressure, fast time), this type of "classical" model solved on a macroscopic scale gives any information on the energy distribution within the silica grains. Consequently, we introduced a model with two scales coupling the macroscopic and microscopic phenomena. It is built on a multi-species flow model coupled with the interaction laws representing the porous media and a local thermal model (pore-scale) based on the total enthalpy conservation of the gas-solid system.

Temperature distribution of the plasma and the silica grains during the arc period.

The knowledge of the temperature distribution in the silica grains allows to control the of vaporization and recondensation process of the silica vapor during the phenomenon. This model allows to represent heat and mass exchanges between the two phases.

Evolution of the gas temperature in the fuse.

Creation Elforia Design