Pool boiling heat transfer to dilute copper oxide aqueous nanofluids

A set of experiments have been performed to quantify the pool boiling heat transfer coefficient of dilute copper oxide water-based nanofluids at mass concentrations of 0.1-0.4%. To stabilize the two-step nanofluids, pH control, stirring and sonication were utilized. For investigating the influence of surfactant as a surface active agent additive on the pool boiling heat transfer coefficient of nanofluids, SDS, SDBS and Triton X-100 were used. Influence of some operating parameters such as applied heat flux, mass concentration of nanofluids and other parameters such as roughness of surface, boiling contact angle and deposition on the pool boiling heat transfer coefficient of nanofluids were experimentally investigated. Results demonstrated a significant deterioration of heat transfer coefficient of nanofluids comparing with the base fluid in the absence of surfactants, however, in the presence of surfactant, higher pool boiling heat transfer coefficient was reported. According to results, roughness of surface is strongly controlled by nanofluid concentration due to deposition of nanofluids on the heating section. Rectilinear changes of deposition with time in term of fouling resistance were seen at both regions with natural convection and nucleate boiling dominant heat transfer mechanisms. (C) 2014 Elsevier Masson SAS. All rights reserved.