Kinetic surface model in FESTIM: Verification and Validation

TL;DR

This paper presents the verification and validation of a new kinetic surface model in FESTIM, an open-source hydrogen transport simulation software, demonstrating its accuracy and reliability through theoretical and experimental comparisons.

Contribution

The paper introduces a new kinetic surface model in FESTIM, validated through manufactured solutions, experimental case reproductions, and cross-code comparisons.

Findings

Model implementation verified with manufactured solutions.

Successfully reproduces experimental hydrogen retention cases.

Shows excellent agreement with other simulation packages.

Abstract

The open-source code FESTIM (Finite Element Simulation of Tritium In Materials) is a powerful user-friendly software for hydrogen transport simulations. Up to now, it was capable of addressing various hydrogen transport problems with surface processes dependent on the concentration of solute species. However, the kinetics of surface hydrogen concentration should be considered under certain conditions. The recent 1.3 release of FESTIM introduced a new kinetic surface model, implemented in a flexible way for various applications. The correctness of the implementation is first proven using the method of manufactured solutions. Then, reliability of the model is demonstrated by reproducing four experimental cases on dynamics of hydrogen isotope retention in different materials. An additional cross-code comparison with two other simulation packages, MHIMS and TESSIM-X, shows an excellent agreement and strengthens the validity of the model.