Thermal and fluid dynamic processes occurring at liquid boiling over micro-and-nano enhanced surfaces

Abstract

Paper presented to the 10th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Florida, 14-16 July 2014.This paper addresses the basic nucleation and bubble dynamics mechanisms, focusing on the effect of enhancing the surface. The consequences at the heat transfer mechanisms are also discussed. The review performed here stresses the need to accurately describe the effect of surface topography and wettability, as this is a critical step to lessen the strong empirical nature that is present in most of the theoretical predictions. This accurate description also requires adequate diagnostic techniques. Combining Particle Image Velocimetry – PIV with high speed imaging and thermography has been recently reported in the literature to render precise measurements of several quantities such as bubble departure diameters and frequencies, and even thickness of the micro layer, which are of major importance to validate theoretical correlations. The experimental analysis performed here also highlights the important role of the interaction mechanisms in bubble dynamics and consequently in the heat transfer mechanisms.