Surface tension of evaporating nanofluid droplets

    Authors

    R. H. Chen; T. X. Phuoc;D. Martello

    Comments

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    Abbreviated Journal Title

    Int. J. Heat Mass Transf.

    Keywords

    Nanofluids; Surface tension; Evaporating droplet; Stefan's formula; THERMAL-CONDUCTIVITY ENHANCEMENT; BOILING HEAT-TRANSFER; NANO-FLUIDS; CONTACT-ANGLE; NANOPARTICLES; TEMPERATURE; WATER; MICROLAYER; PARTICLES; DYNAMICS; Thermodynamics; Engineering, Mechanical; Mechanics

    Abstract

    Measurements of nanofluid surface tension were made using the pendant droplet method. Three different types of nanoparticles were used - laponite, silver and Fe(2)O(3) - with de-ionized water (DW) as the base fluid. The reported results focus on the following categories; (1) because some nanoparticles require surfactants to form stable colloids, the individual effects of the surfactant and the particles were investigated; (2) due to evaporation of the pendant droplet, the particle concentration increases, affecting the apparent surface tension; (3) because of the evaporation process, a hysteresis was found where the evaporating droplet can only achieve lower values of surface tension than that of nanofluids at the same prepared concentrations: and (4) the Stefan equation relating the apparent surface tension and heat of evaporation was found to be inapplicable for nanofluids investigated. Comparisons with findings for sessile droplets are also discussed, pointing to additional effects of nanoparticles other than the non-equilibrium evaporation process. (C) 2011 Elsevier Ltd. All rights reserved.

    Journal Title

    International Journal of Heat and Mass Transfer

    Volume

    54

    Issue/Number

    11-12

    Publication Date

    1-1-2011

    Document Type

    Article

    Language

    English

    First Page

    2459

    Last Page

    2466

    WOS Identifier

    WOS:000289820100025

    ISSN

    0017-9310

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