Title

Surface tension of evaporating nanofluid droplets

Authors

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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