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Highly wettable CuO:graphene oxide core–shell porous nanocomposites for enhanced critical heat flux
Author(s) -
Cheedarala Ravi Kumar,
Park Eun Ju,
Park YoungBin,
Park Hyung Wook
Publication year - 2015
Publication title -
physica status solidi (a)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.532
H-Index - 104
eISSN - 1862-6319
pISSN - 1862-6300
DOI - 10.1002/pssa.201431858
Subject(s) - materials science , boiling , oxide , nanofluid , critical heat flux , chemical engineering , graphene , wetting , nanocomposite , surface roughness , nanotechnology , contact angle , copper oxide , nanoparticle , composite material , heat flux , heat transfer , metallurgy , chemistry , thermodynamics , engineering , physics , organic chemistry
Copper oxide nanoparticles nanofluids (CuO‐NPs‐NF) are promising candidates for pool boiling critical heat flux (CHF) applications due to their multifaceted advantages like easy tunability, eco‐friendliness, cost‐effectiveness, easy chemical modification and higher thermal conductivities. In addition, entrapping the CuO‐NPs in/on to graphene oxide (GO) improves the CHF values compared to CuO‐NPs alone. This paper reports a high performance hybrid NFs based on CuO and GO nanocomposites (CuO:GO‐NCs‐NFs), exhibiting higher pool boiling CHF values even at very low concentrations. The proposed novel NFs have higher thermal conductivities compared with the DI water. The 0.06 wt% CuO:GO‐NCs‐NF shows the highest CHF value, ca.160%, which is much higher than that of pure CuO‐NPs‐NF (99%). Atomic force microscope (AFM) and field‐emission SEM (FE‐SEM) micrographs of the wire after the pool boiling experiments revealed a rough surface having high wettability and lower contact angle (CA) with 47° due to the formation of a layer‐on‐layer network on the wire surface. In addition, we have developed a method for in situ generation of core–shell template model CuO‐NPs using Ostwald's ripening method in isopropanol–water system. Eventually, the CuO:GO‐NCs‐NF could show robust and high performance CHF pool boiling even at low concentrations that are required in realistic applications. Schematic illustration of pool boiling CHF values of CuO‐NPs and CuO:GO–NCs on nichrome wire surface. (a) Built‐up layer roughness average by atomic force microscope (AFM) and (b) FEM‐SEM. (c) comparison of pool boiling CHF experiment.