From macroscopic to microscopic flows: something old,something new, and something very new
by Professor David V. Boger
Abstract: The seminar examines outcomes and challenges on three different areas of
industrial rheology, highlighting the importance of the Deborah number.
The Deborah number is the ratio of a characteristic time of the material
to a characteristic time of the process.
Something old: pipeline flow of concentrated suspensions with application
in the minerals, coal and oil industries is examined. The challenge is to
pump paste in laminar flow and to understand wall boundary conditions.
Something new: drop impact on hydrophobic and hydrophilic surfaces is
examined for low constant viscosity elastic liquids. The application is
in the delivery of agricultural chemicals where it is intended that drops
impact a leaf and do not bounce off the surface.
Something very new: microchannel abrupt contraction-expansion flows are
examined for use as micro-extensional rheometers and for gaining an
understanding of fluid elasticity in microscopic flows. The work is a
collaboration between MIT and The University of Melbourne. The results
clearly show that the length scale is extremely important for microchannel
flows of low viscosity elastic liquids.
For More Information: Ole Warnaar tel. 8344 5214 or Paul Pearce tel. 8344 4470