Augmented boiling heat transfer on the wetting-modified three dimensionally-interconnected alumina nano porous surfaces in aqueous polymeric surfactants

• Published in: International journal of heat and mass transfer Vol. 63; pp. 224 - 232
• Main Authors: Zhang, Bong June, Park, Jiyeon, Kim, Kwang Jin
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.08.2013
• Subjects: Aluminum oxide; Anodizing; Boiling; Bubbles; Drop impact test; Heat transfer; Nano-porous surfaces; Nanostructure; Nucleate pool boiling heat transfer enhancement; Pools; Surface chemistry; Surface wettability; Surfactant; Surfactants; Wetting; Drop impact test; Nano-porous surfaces; Anodizing; Nucleate pool boiling heat transfer enhancement; Surface wettability; Surfactant; Aluminum oxide
• ISSN: 0017-9310; 1879-2189
• DOI: 10.1016/j.ijheatmasstransfer.2013.03.064

Pool boiling in an aqueous surfactant solution is one of efficient approaches to increase pool boiling performance in nucleate boiling regime since additive polymer surfactants modify interfacial wetting properties between heating surface and fluids. Enhanced wetting increases bubble departure frequency and prevents bubble coalescence. Most pool boiling tests in aqueous surfactant solutions have been carried out on non-porous surfaces (plain surfaces) and heat transfer performances reported were not drastic. In this study, the Alumina Sponge-like Nano Porous Surface (ASNPS) was used as a heating surface in aqueous SDS solutions. The ASNPS’s surface wetting was modified with a hydrophobic Self-Assembly Monolayer (SAM) coating. The wetting-modified ASNPS shows substantial increase in active nucleation sites through three-dimensionally interconnected porous network. Eventually, significant heat transfer enhancement (7.3times) is achieved due to the combined effects. For bubble motion characterization associated with surfactants, various approaches have been made using Dynamic Light Scattering (DLS), Transmission Electron Microscopy (TEM), Static Water Contact Angle (SWCA) measurements, and high speed image analysis of liquid impingement.