Thermographic analysis of thin liquid films on a rotating disc: approach and challenges

Abstract

Paper presented at the 8th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Mauritius, 11-13 July, 2011.

This paper examines the temperature profiles and flow characteristics of thin liquid films on a rotating surface by means of an Infrared (IR) thermal imaging camera. The challenges of obtaining accurate temperature measurements using thermographic techniques, in particular for thin liquid films of varying thicknesses, are outlined in this study. The captured images of the liquid film provide a visual insight into the heat transfer mechanism as the cold liquid moves from centre of a rotating disc towards its edges. The effect of liquid film viscosity, rotational speed, feed flowrate and disc temperature on heat transfer efficiency from the heated disc to the cold film is investigated. The temperature profiles obtained by the Infrared camera are compared to those estimated by a theoretical model of disc/film heat transfer. The results provide an excellent platform for qualitative analysis of heating thin liquid films in highly accelerated centrifugal fields. The quantitative analysis is, however, associated with some degrees of uncertainty due to the limitations described in this paper.