Interfacial Energy and Micelle Conditions of Ternary Mixtures for Improved Heat Transfer

Abstract

The search for suitable mixtures as boiling fluids leads to the development of ternary liquid mixtures that could handle even higher heat fluxes than binary mixtures through the formation of stable bubble-micelles departing from the heater’s surface. The amount of experimental work for testing the combinations is reduced using the interfacial tension prediction capabilities of simulation software, although it is not possible to predict singularities in the interfacial tension behavior of the mixtures. The ethanol aqueous mixture shows a singularity in its interfacial tension value at 16% ethanol by weight. In this work was combined with glycols for enhancing boiling heat transfer by decreasing the mixture interfacial tension. Also, the effect of the surfactants Dodecyl Benzene Sodium Sulfonate (DBSS) and Sodium Lauryl Sulfonate (SLS) in the mixture interfacial tension was studied. The measurements of sessile drop contact angles of mixtures with added surfactant allowed finding the singularities in the surface tension values that are related to critical micelle concentrations and the increment in boiling heat transfer. The propilenglycol-ethanol-water mixture produced the lowest values of contact angles, while for the etilenglycol-ethanol-water mixtures no such reduction was obtained with the same amount of the glycol. The use of DBSS and SLS at their critical micelle concentration decreased further the interfacial tension of the propilenglycol ternary mixture to generate a mixture that could improve the convective heat transfer coefficient.