Application of Laser Induced Fluorescence in experimental analysis of convection phenomena

Abstract

One of the most promising technique for temperature measurement is the Laser Induced Fluorescence (LIF) which utilize basic concept of optical, non-intrusive measurements and give possibility to visualize the temperature distribution in the whole two-dimensional plane at once. A major problem of a LIF is it still unsatisfactory accuracy for temperature gradient and heat transfer measurement. The LIF fluorescent re-emission is a function of temperature but, in all measurements a lot of imperfection follow the image recording: background noises, light intensity variation, non uniformity and shadowgraph effect near the non-isothermal walls. In the present paper the influence of all key effect on the temperature measurement will be verified in order to obtain the method uncertainty. To evaluate that experimental measurement of convection phenomenon using LIF and thermocouples focussing on heat transfer measurement will be presented. Results show that all processing steps (pre-processing, processing and post-processing) are crucial for reducing the error related to the temperature measurement.