Surface tension of evaporating nanofluid droplets
- Univ. of Central Florida, Orlando, FL (United States)
- National Energy Technology Lab. (NETL), Pittsburgh, PA, (United States)
Measurements of nanofluid surface tension were made using the pendant droplet method. Three different types of nanoparticles were used - laponite, silver and Fe2O3 - 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.
- Research Organization:
- National Energy Technology Laboratory (NETL), Pittsburgh, PA, Morgantown, WV, and Albany, OR (United States)
- Sponsoring Organization:
- USDOE Assistant Secretary for Fossil Energy (FE)
- OSTI ID:
- 1014881
- Report Number(s):
- NETL-TPR-3252
- Journal Information:
- International Journal of Heat and Mass Transfer, Vol. 54, Issue 11-12; ISSN 0017-9310
- Publisher:
- Elsevier
- Country of Publication:
- United States
- Language:
- English
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