Non-linear finite element modelling of light-to-heat energy conversion applied to nanoencapsulated phase change materials
Authors: | Forner Escrig, J., Mondragón, R., Palma, R. | |
Conference: | VIII International Conference on Computational Methods for Coupled Problems in Science and Engineering. COUPLED PROBLEMS 2019 | |
Location and date: | Sitges (España), June 2019 |
Abstract
In nature, physical phenomena tend to exhibit their effects simultaneously and, depending on the situation of study, their interactions cannot be neglected. For instance, nanofluids, which are composed of both fluid and nanosolids, are currently used for thermal energy storage in concentrated solar power plants and couple thermal and mechanical fields. Notice that owing to some limitations of solar collectors, black liquids combined with nanoparticles are used currently to absorb solar energy by light-to-heat conversion of energy. On this ground, the aim of the present work is to develop a numerical formulation within the finite element method (FEM) to study the light-to-heat energy conversion, phase-change and thermal stresses in nanosolids. For this purpose and in a first and good approximation, it is assumed that the light is converted into heat by the Joule heating -a non-linear term which quadratically depends on the electric field. Therefore, the set of three coupled governing equations is composed of: balance of linear momentum for the mechanical field, balance of energy for the thermal field and balance of electric current for the electric field. These equations are rewritten in a weak form, which is more amenable in the context of the FEM, and they are implemented in a numerical code. Finally, several benchmarks are presented to validate the numerical results against analytical solutions developed by the authors.