Temperature Field Measurements In The Cross-Section Of Falling Liquid Films By Laser-Induced Fluorescence

Abstract

Thin wavy liquid films a reused in many applications as heat a nd mass transfer promoters thanks to their great performances for a small liquid consumption. To further understand the exact mechanisms of coupling between the wavy fluid dynamics and the heat transfer, a laser-induced fluorescence technique has been developed. The technique enables a measurement of the temperature field inside of a wavy film flowing down an inclined plane with a high spatial resolution. This paper reports on the development of the technique. Water liquid films were investigated under two-dimensional waves conditions. The measurements reveal the regions where mixing is enhanced by convective circulation zones and enables the evaluation of the intensification of the heat transfer due to the waves.