Radiative properties of radially nonisothermal alumina particles with multiphase

Accurate prediction of radiative properties of alumina (Al2O3) particle with phase transition is essential to both spray deposition of coatings and solid aluminized rocket plume diagnostics. In this paper, a theoretical model based on the electromagnetic theory is applied to determine thermal radiation of a radially inhomogeneous alumina particle having a radial temperature distribution, where a concise and efficient algorithm is developed for the calculation. The internal absorption efficiencies for single phase and multiphase particle are calculated and discussed. The absorption efficiency at the surface of multiphase alumina spherical particle is calculated by the effective-medium sphere mode, and the result is compared with that of multilayered sphere model, which shows that effective-medium sphere mode gives similar results when each layer's thickness is much less than the wavelength of the incident light. The effect of temperature difference between the center and the surface on the spectral radiant flux of multiphase alumina particle is also analyzed in this paper. (C) 2011 Elsevier Ltd. All rights reserved.