Bubble nucleation characteristics in pool boiling of a wetting liquid on smooth and rough surfaces
Date of this Version4-2010
This document has been peer-reviewed.
Quantitative measurements are obtained from high-speed visualizations of pool boiling at atmospheric pressure fro m smooth and roughened surfaces, using a perfluorinated hydrocarbon (FC-77) as the working fluid. The boiling surfaces are fabricated from aluminum and prepared by mechanical polishing in the case of the smooth surface, and by electrical discharge machining (EDM) in the case of the roughened surface. The roughness values (R-a) are 0.03 and 5.89 mu m for the polished and roughened surfaces, respectively. The bubble diameter at departure, bubble departure frequency, active nucleation site density, and bubble terminal velocity are measured from the monochrome movies, which have been recorded at 8000 frames per second with a digital CCD camera and magnifying lens. Results are compared to predictions from existing models of bubble nucleation behavior in the literature. Wall superheat heat flux, and heat transfer coefficient are also reported. (C) 2009 Elsevier Ltd. All rights reserved.
Engineering | Nanoscience and Nanotechnology