Nanoparticle Deposition by Boiling on Aluminum Surfaces to Enhance Wettability

Surface wettability of materials is important in a myriad of HVAC&R processes. This study is focused on how to manipulate wettability by nanofluid boiling nanoparticle deposition on aluminum surfaces. The focus is on aluminum, because it is commonly used as the material for heat transfer in air conditioning and refrigeration systems. The boiling deposition process occurs under atmospheric pressure, in a reservoir large compared to the sample size. The effect of nanoparticle concentration, boiling duration and surface initial roughness are studied by varying parameters one at a time while controlling the others. Al2O3 nanoparticles aredeposited on the aluminum surface, as confirmed by microscopy. The static contact angle of water is measured using a goniometer to characterize the wetting behavior. It is observed that the layer of Al2O3 nanoparticle deposited on aluminum surfaces enhances the wettability on the surface, and the higher the concentration of nanoparticle in the fluid during boiling deposition, the better the wetting of the surface. Surface roughness before and after the nanofluid boiling process is also investigated. The relationship between the surface topography and water wettability is discussed.