Event Details
Microscale Flow Visualization
Presenter: David Sinton - Department of Mechanical and Industrial Engineering, University of Toronto
Supervisor:
Date: Thu, February 13, 2003
Time: 11:00:00 - 00:00:00
Place: EOW 430
ABSTRACT
Abstract:
Advances in the emerging field of microfluidics are making possible the miniaturization of laboratory analyses. Advantages of the lab-on-a-chip concept include reductions in chemical requirements, increases in speed, and potential for massive automation and parallel processing. The performance of these devices is critically dependant on the nature of the fluid flow, which is typically a combination of classical hydrodynamics and electrokinetic effects. Microscale flow visualization enables both fundamental research into the characteristics of fluid flow in microchannels, and applied research into on-chip processes (mixing, dispensing, and separating). Here, an experimental technique for determining cross-stream velocity profiles in microchannels (diameters on the order of a human hair D = 20 mm - 200 mm) is presented. The technique employs a specialized caged-fluorescent dye, which is 'photo-injected' by exposure to an intensely focused ultraviolet laser light. The method is applied to study pressure-driven flow, electroosmotic flow, ohmic heat generation, multiphase transport and other aspects of microfluidic transport phenomena in a range of channel geometries. In addition, direct visualization of on-chip microfluidic processes are presented, as well as improved procedures resulting from that work.