Non-intrusive thermometry in water: a novel temporal method using rise time-decay time ratio of ZnO phosphorescence in comparison with RhB PLIF and ZnO spectral imagery

Abstract

The temporal characteristics of ZnO phosphor emission and the possibility to obtain instantaneous and mean 2D temperature fields in fluids have been analysed in this article. Spectrometer tests have been performed by mixing ZnO micro-particles in liquid (water) to analyse the emission characteristics of the phosphor upon excitation by a 266 nm laser. Using a fast gating camera, it has been shown that 2D phosphor thermometry can be performed through temporal methods using ZnO phosphors, which were thought previously to be unachievable. Additionally, a two-camera temporal method is proposed by exploiting the rise and decay times of the ZnO phosphor emission upon excitation. Sensitivity of the metrology is proposed and compared with commonly used Rhodamine B fluorescence and ZnO spectral methods.