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

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 4 Hz 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 40 kHz. The effect of exposure time was investigated to yield an optimum value of 2 ms in this study. Finally, this new method was demonstrated in temperature measurements of the steady and impulsively started impingement jet heat transfer.