Liquid/surface interaction during pool boiling of DI-water on nanocoated heating surfaces

Autor(es)

Souza, R. R. ^[1] ; Manetti, L. L. ^[1] ; Kiyomura, I. S. ^[1] ; Cardoso, E. M. ^[1]

Afiliação do(s) autor(es)

^[1] UNESP Sao Paulo State Univ, Postgrad Program Mech Engn, Ave Brasil 56, BR-15385000 Ilha Solteira, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Journal of the Brazilian Society of Mechanical Sciences and Engineering; v. 40, n. 11 NOV 2018.
• Citações Web of Science: 0

Resumo

This study focuses on the effect of the nanostructured heating surface on the heat transfer coefficient (HTC) considering the nanofluid concentration used for coating surfaces and the heating surface morphology. Copper blocks with roughness values of R-a = 0.05 m (smooth surface) and R-a=0.23m (rough surface) were used as heating surfaces, and deionized water (DI-water) at atmospheric pressure and saturation temperature was used as the working fluid. Nanostructured surfaces were obtained by boiling process of Al2O3-DI-water-based nanofluid for different volumetric concentrations 0.0007vol% and 0.007vol% (corresponding to low and high nanofluid concentration, respectively) to analyze the interaction between the heating surface and the working fluid. With this purpose, six different copper surfaces were submitted to metallographic, roughness, wettability, and thermal image analysis. The experimental results showed that the enhancement or deterioration of boiling heat transfer is strongly affected by the nanofluid concentration-used to nanocoat the heating surface-and the original heating surface morphology. The nanocoating process increases the surface roughness and changes the surface wettability. Moreover, as the nanofluid concentration increases, the wettability and nanolayer thickness also increase. The wall temperature distribution, obtained by thermal image analysis, agrees with the HTC behavior. For the coated rough surfaces, it is observed deterioration of the HTC regardless of nanofluid concentration. The increase in the surface temperature and the consequent degradation of the HTC are more pronounced for higher nanoparticle concentrations. (AU)

• Processo FAPESP: 13/15431-7 - Análise da aplicação de nanotecnologia em processos térmicos e de conversão de energia
• Beneficiário: Elaine Maria Cardoso
• Modalidade de apoio: Auxílio à Pesquisa - Jovens Pesquisadores
• Processo FAPESP: 17/13813-0 - Utilização de superfícies estendidas - espumas metálicas - para intensificação da transferência de calor por ebulição
• Beneficiário: Leonardo Lachi Manetti
• Modalidade de apoio: Bolsas no Brasil - Doutorado