Temperature imaging of mobile BaMgAl₁₀O₁₇:Eu phosphor aggregates under high radiation flux

Planar laser-induced phosphorescence (PLIP) has been used for the temperature measurement of suspended phosphor aggregates. Two-dimensional surface temperature of fluidized phosphor aggregates was measured through a pair of spatial and wavelength resolved images in an environment where phosphors are heated by high-flux radiation. The heating was supplied by a multi-diode laser system which provides a well-characterized high-flux radiation up to 28.87 MW/m². Phosphors made of BaMgAl₁₀O₁₇:Eu (BAM) were selected as the material and suspended in a fluidized bed. Single-shot temperature imaging of BAM aggregates were inferred and compared at several heat fluxes. With the increasing heat flux up to 28.87 MW/m², the BAM aggregates were found to exhibit a wider range of temperature distribution, and the maximum average aggregate temperature achieved 723 K, while the maximum temperature of a single aggregate could reach up to 1063 K. The wider temperature distributions that observed under higher radiation fluxes were caused by the elevated temperature of cooling air and the non-uniform aggregate surfaces. This non-intrusive method of measuring temperature offers advantages over other available methods in the study of heat transfer processes involving high-temperature reactions.