# Improvement of Temperature Measurement Accuracy of Hot Airflow Using Ultrafine Thermo-Sensitive Fluorescent Wires of Lumisis Phosphor

## TL;DR

This study improves temperature measurement accuracy in hot air using ultrafine fluorescent wires made of Lumisis phosphor.

## Contribution

The study introduces an optimized 1:1.25 Lumisis phosphor mixture for accurate two-color LIF temperature measurements.

## Key findings

- Two-color LIF was feasible using the red and green fluorescence intensity differences of Lumisis.
- The average measurement error of the fluorescent wire was 0.20 K.
- The method accurately captured temperature changes in hot air jet phenomena.

## Abstract

In this study, the fluorescence properties of Lumisis, a phosphor that can be easily applied to ultrafine wires, were evaluated. By evaluating the wavelength characteristics of Lumisis phosphor, we investigated the possibility of applying it to a dual-wavelength laser-induced fluorescence (LIF) measurement system and evaluated the accuracy of temperature measurements. The difference between the decrease in the percentage intensities of the red and green fluorescence of Lumisis phosphors showed that two-color LIF was possible. The Lumisis phosphor–mixture ratio was optimized as 1:1.25, and the average measurement error of the fluorescent wire was 0.20 K, as evaluated through uncertainty analysis. Finally, the application of this measurement method to hot air jet phenomena showed that this method accurately captures the temperature changes in hot air, thus proving its validity.