Effect of interfacial energy on the viscosities of two-phase mixtures - A physical modeling approach

With a view to understanding the viscosities of metal emulsions in viscous slags, the present work was carried out to study the phenomena underlying t he viscous flow in a two-phase mixture with widely differing viscosities. E xperimental study was carried out to determine the effective viscosities of emulsions of silicone oils of known viscosities (345 and 1010 mPa . s at 2 93 K) with small amounts of water evenly distributed in the same. The visco sities of these emulsions were measured at a constant temperature by the ro tating-cylinder method. The uniformity of the preparation of the emulsions was confirmed by the reproducibility of the results. The measured viscositi es were generally found to be independent of the torque under the experimen tal conditions, so that the two-phase mixture could be considered as a Newt onian liquid. The variation of viscosities with temperature and the effect of the addition of a surface-active substance were also studied in this wor k. The viscosities were found to be higher than those of both pure water an d silicone oil. The experimental results were used to examine the applicabi lities of the theoretical models developed by Einstein, Taylor, and Oldroyd . It was found that interfacial energy would play an important role in the viscous flow of the two-liquid mixture.