Computational analysis of hybrid heating of a heterogeneous core-shell configuration for improving temperature uniformity Análisis computacional del calentamiento híbrido de una configuración heterogénea de núcleo-caparazón para mejorar la uniformidad de la temperatura

Abstract

Throughout this study, we propose using hybrid heating (microwaves – thermal radiation) on a heterogeneous structure. Our goal is to improve the effectivity of its thermal treatment. We analyze a core-shell assembly with different thermal and electrical properties. A solid sphere makes up the core of the arrangement. Such a core is surrounded by three layers of different materials. Because of the properties of the original system, we propose modifying the core so that it absorbs microwaves. The layers are all homogeneous and microwave transparent. The first two exhibit a low thermal conductivity, while the outermost one is a good thermal conductor. We also propose adding a thin layer of susceptor between the first two layers, striving to alleviate the low thermal conduction problem. Furthermore, the dielectric loss constant of this new layer is temperature-dependent. We assume that the composed sphere hangs within the electromagnetic cavity and continuously rotates, so it homogeneously receives microwaves and thermal radiation (from an electrical resistance). Thus, the thermal model is given by a set of time-dependent partial differential equations. Transient temperature profiles are analyzed under different experimental scenarios. There is a clear advantage of using the proposed hybrid heating in this particular case.