Eventos Anais de eventos
COBEM 2017
24th ABCM International Congress of Mechanical Engineering
Evaluation Of Surface Roughness And Nanofluid Concentration On The Surface Wettability And The Wall-Temperature Distributions
Submission Author:
Alex Cunha , SP , Brazil
Co-Authors:
Igor Seicho Kiyomura, Elaine Maria Cardoso, Alex Cunha
Presenter: Alex Cunha
doi://10.26678/ABCM.COBEM2017.COB17-5898
Abstract
The pool boiling phenomena can be large affected by fluid/surface interaction caused by changes in the surface roughness or in the properties of the working fluid by adding nanoparticles to the base fluid. This work focuses on the effect of surface roughness and nanofluid concentration on the surface wettability and the wall-temperature distributions. It also discusses their effects on nanofluid pool boiling heat transfer. The tests were performed on copper heating surfaces with different roughness values, in order to analyze the interaction between the surface roughness and nanoparticles deposited on the heating surface. Nanostructured surfaces were produced through the boiling process of Al2O3-water based nanofluid for different mass concentrations. The surfaces were submitted to metallographic, roughness, wettability and thermal image analysis. As nanofluid concentration increases, the surface roughness also increases and the contact angle decreases, showing a hydrophilic behavior. It was observed that the smooth surface has the lowest heat transfer performance compared to the other surfaces. The nanolayer formed on rough surfaces increases the thermal resistance of the surface, degrading the heat transfer; however, for smooth surfaces, the nanoparticle deposition increases the boiling heat transfer only for low nanofluid concentrations.
Keywords
nanofluid pool boiling, HTC, surface wettability, Thermal Analysis
