3D visualized characterization of radiation energy transport in a real semitransparent foam strut under high irradiation beam

Abstract

A key challenge to model the heat transfer in refractory ceramic foams at high temperature is to characterize properly the transport of thermal radiation, especially when the foams are directly exposed to a high irradiation beam such as concentrated solar radiation. Characterization of the radiation transport in a single strut is representative and fundamental for the radiation transfer modelling of foams. This study numerically investigates the radiation transport and temperature response in a real foam strut under high irradiation beam. The digitalized strut was obtained by the X-ray micro-computed tomography imaging measurements, and then meshed within the strut volume and on the surface. The Discrete Ordinate Method is used to solve the Radiative Transfer Equation, since the strut material (alumina ceramic) is by nature semitransparent for incident radiation, resulting absorbing, scattering and emitting inside the solid phase. The volumetric propagation of radiation intensity is tracked and the absorbed radiation energy is recorded. Besides, the temperature response of the strut irradiated by a beam with periodic heat flux is investigated. The knowledge of radiation transport and temperature response in foam struts can provide fundamental information for understanding the pore-level heat transfer and for developing high-quality simulation and experiments.