Thursday February 17, 2011 4:00-5:00 p.m.
ME-EM building, Room 112
Associate Professor Kendra Sharp
Oregon State University
Prof. Sharp’s presentation will focus on three-dimensional measurements of the flowfield in a stirred tank reactor, however, several other current projects will also be briefly introduced. These projects include: induced-charge electroosmosis for flow control in microchannels; a microchannel-based dialyzer; high-Reynolds number flow in a 90° bend; and ‘ micro’-hydro power for rural electrification.
Volumetric 3-component velocimetry measurements have been taken of the flow field near a Rushton turbine in a stirred tank reactor. This particular flow field is highly unsteady and three-dimensional, and is characterized by a strong radial jet, large tank-scale ring vortices, and small-scale blade tip vortices. The experimental technique uses a single camera head with three apertures to obtain approximately 15,000 three-dimensional vectors in a cubic volume. These velocity data offer the most comprehensive view to date of this flow field, especially since they are acquired at three Reynolds numbers. Mean velocity fields and turbulent kinetic energy quantities are calculated. The volumetric nature of the data enable tip vortex identification, vortex trajectory analysis, and calculation of vortex strength. Three identification methods for the vortices are compared. The visualization of tip vortices up to 140 degrees past blade passage in the highest Reynolds number case is notable and has not previously been shown.