Prediction of radiation spectra of composite with periodic micron porous structure

In this work, one three-dimensional periodic composite structure consisting of alumina frame and inscribed nickel spheres is proposed for designing the micron composite porous structure. The finite-difference time domain method is applied for predicting the radiation spectra of proposed composite structure and distribution of absorbed radiative power. The spectral characteristics of composite structure are compared with the hollow ceramic frame structure and stacked metal spheres for analysis of radiative properties of discussed micron composite porous structure, then the effects by changing the number of layers and inner structure are summarized. Strong spectral selectivity is observed, while radiative properties of composite structure are harmonic results of hollow ceramic frame structure and stacked metal spheres. The absorptivity changes with increasing layers hardly, while the reflectivity and transmissivity are affected by number of layers obviously until the number of layers reaches three. When the number of layers exceeds three, the effects of increasing layers are ignorable. Besides, effects on the distribution of absorbed power inside composite porous structure are produced by upper two layers mainly. Furthermore, the radiation spectra are changed by placing hollow ceramic frame layers on the composite structure layer. The proposed composite structure and prediction of radiative properties can be helpful for designing the structure of micron porous materials and regulating the radiative transfer.