Eventos Anais de eventos
COBEM 2017
24th ABCM International Congress of Mechanical Engineering
EXPERIMENTAL ANALYSIS OF NUCLEATE BOILING ON NANOSTRUCTURED SURFACES UNDER CONFINED CONDITIONS
Submission Author:
Jessica Martha Nunes , SP
Co-Authors:
Leonardo Manetti, Elaine Maria Cardoso, Jessica Martha Nunes
Presenter: Jessica Martha Nunes
doi://10.26678/ABCM.COBEM2017.COB17-1909
Abstract
Nanocoating techniques have been used to increase the heat transfer coefficient by changing the surface morphology, which could potentially increase the heat transfer in case of pool boiling systems. The present work aims to study the effect of nanostructured surfaces and the gap size during the nucleate boiling of DI-water, at atmospheric pressure and saturation temperature. The tests were performed on copper heating rough surfaces. The nanostructured surfaces were produced by maghemite nanoparticle deposition, for two different mass concentrations, via nanofluid boiling process. A gap size of 1.0 mm (Bo = 0.4) and of 13 mm (corresponding to an unconfined case, Bo = 5.2) were analyzed in this study. Concerning the heat transfer coefficient for the unconfined case, it was observed that both nanostructured rough surfaces showed deterioration of HTC when compared with the surface without deposition due to the fouling resistance formed on the heating surface. For the confined case, the enhanced boiling is a consequence of the deformed bubbles which increase the area of the liquid film between the vapor bubble and the heating surface, which increased the HTC up to 22%.
Keywords
Boiling Heat Transfer, Nanostructured surface, Confined nucleate boiling
