An analysis of long term temperature measurement using laser induced fluorescence

Abstract

The temperature measurement is extremely important because it occurs in many technical and engineering processes, including combustion chambers, mixers or chemical reactors as well as environmental flows. In contrast to the point measurement method, Laser Induced Fluorescence (LIF) allows temperature determination in the whole plain 2D, or even 3D, domain. A major advantage of LIF is also its relatively high accuracy. This technique involves dissolving a temperature- sensitive fluorescence dye to a fluid. It is known that in LIF the fluorescent reemission is a function of temperature but, in many cases, it can also be a function of time, due to dye properties degradation. In the present research, a long-term temperature measurement using LIF was performed in order to analyse the method uncertainty related to time. The results of the stability of Rhodamine-B in nonisothermal experimental measurements in water solution, together with the chemical analysis using spectrophotometry, are presented.