JEFFREY MORRIS
City College of NEw York

EXTREME TRANSITIONS OF FLOW PROPERTIES: GAS HYDRATE JAMMING AND DISCONTINUOUS SHEAR THICKENING

Large changes in properties are an issue of substantial concern in engineering of flow processes. This talk will discuss extreme transitions in flow properties observed in multiphase mixtures. Two quite different transitions, connected through the physical concept of approach to a jammed state, will be considered. In the first case, properties of gas hydrate-forming water-in-oil emulsions will be described based on our experiments. This is a critical problem in petroleum pipelines: a transition occurs due to a phase transition as time progresses. Morphology of the hydrate under emulsified conditions is typically needle-like and porous.  The developed porosity allows even modest internal phase (water) emulsions to “jam”, much like the undesirable plugging of pipelines.  The rheological properties will be correlated to direct imaging of the hydrate crystal growth at a water-oil interface. The second case is abrupt or “discontinuous” shear thickening (DST), which occurs as shear rate is increased in suspensions at large solid fraction. The fundamental basis of DST has been mysterious and controversial.  A simulation based on a minimal model has been shown to reproduce DST as the rate is increased. The mechanism is found in a contact network between the particles, which changes dramatically as the critical shear rate is surpassed. 

JEFFREY MORRIS is a professor and chair of the Chemical Engineering department at the City College of New York, CUNY. He is also the director of the Levich Institute and an Associate Editor of the Journal of Fluid Mechanics. He authored the text, A Physical Introduction to Suspension Dynamics, with E. Guazzelli. His research focusses on the development of a fluid mechanical description appropriate for complex fluids, particularly suspensions and colloids, with a recent focus on the interaction of frictional interactions with viscous forces. Applying simulation and experiment, combined with ideas of statistical and continuum mechanics, the research seeks to develop understanding of flow-induced microstructure and the resulting mixture rheology. Of particular interest are rheologically-induced phenomena unique to mixtures, including bulk particle migration. He has held Visiting Professor positions at Brown University (Applied Math) the Université de Paris Sud (at the Laboratory FAST) and Université de Provence (at the Laboratory IUSTI). He presently serves as Chair d'Attractivité at the Univ. de Toulouse III.

For more info: uoft.me/lle2016-17

Websites of Interest

• University of Toronto
• Faculty of Applied Science & Engineering
• Department of Chemical Engineering & Applied Chemistry