Flow and characterization of emulsions by nuclear magnetic resonance.

摘要

Experimental studies of flow of oil-in-water emulsions using nuclear magnetic resonance (NMR) are presented. Imaging methods based on this technique were successfully implemented and allowed measurements of velocity fields, concentration maps and droplet size distributions. The interplay between gravity and viscous forces was studied and NMR methods were implemented to obtain experimental results that led to a greater understanding of flow and microstructure of emulsions. The system used was a model oil-in-water emulsion stabilized by a non-ionic surfactant. The geometry was a horizontal concentric cylinder device. It was found that the gravitational effects in non-buoyant emulsions can lead to a complex flow transition when viscous and gravitational effects are comparable. In the study of mixing of initially creamed emulsions, it was found that the characteristics of mixing of such systems differ considerably from systems previously reported in the literature. NMR measurements of spatial distribution of droplet sizes in a creamed emulsion demonstrate the ability of NMR to give an accurate account of the emulsion microstructure. Also, the experimental methodology presented in this work will permit one to explore other aspects of flowing emulsions not considered in this dissertation.