A novel lifetime-based phosphor thermography using three-gate scheme and a low frame-rate camera

Abstract

Lifetime-based method using multiple-frame technique and sophisticated high-speed cameras has been developed for two-dimensional phosphor thermography in recent years, which is however limited due to high cost and long time in data processing. In this study, a novel lifetime-based method using three-gate scheme and a low frame-rate camera was proposed, which is able to significantly reduce equipment cost, simplify data processing, and remarkably increase spatial resolution. Here, Mg4FGeO6:Mn was used as sensor material, which was excited by a pulsed UV LED. A low frame-rate CCD camera at 4Hz was sufficient to conduct phosphor thermometry using a three-gate scheme: one in fully excited region, one in decay region and one for background subtraction. Calibration was performed with a temperature range from 200°C to 550°C, and the results agreed well with data obtained by a high-speed camera sampling at 40kHz. The effect of exposure time was investigated to yield an optimum value of 2ms in this study. Finally, this new method was demonstrated in temperature measurements of the steady and impulsively started impingement jet heat transfer.