Regensburg 2016 – wissenschaftliches Programm

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DF: Fachverband Dielektrische Festkörper

DF 6: Focus Session: Applications of Dielectric Materials in Microwave Technology

DF 6.6: Vortrag

Montag, 7. März 2016, 17:40–18:00, H26

A drying and thermoelastic model for microwave ablation of concrete — •benjamin Lepers — KIT, IHM, Hermann von Helmholtz Platz 1, 76344 Eggenstein Leopoldshafen

The use of high power microwaves to perform explosive spalling of concrete surfaces is a promising technique with applications in the area of concrete facilities decommissioning. The mechanism that creates explosive spalling is due to a combination of the thermal stress from high temperature gradients and the pore pressure generated from the water vaporization and water transport through a porous medium. In this paper a one dimensional model solving the heat and diffusion equations for liquid and vapor phase with the COMSOL Multiphysics finite element software is presented. The modelling of the drying process is based on the spatial reaction engineering approach (SREA). This paper discusses the influence of the relative activation energy parameter and effective diffusion coefficients on the temperature, water content and pore pressure in the case of fast microwave heating of concrete. This model is then used for a 3d geometry with a sealed insulated block of concrete and an conical waveguide antenna to compute the thermal stress, pore pressure and total stress.