(232a) Microparticle Flow in Liquid Medium: 3-D Velocity Measurements in Microchannels

High-speed spinning disk confocal microscopy is an emerging technology in the field of microfluidics. It offers several advantages over widefield micro-PIV techniques, such as the ability to obtain 3-D results of multiphase flow systems with increased signal to noise ratio and spatial resolution. In the past confocal microscopy was limited by its slow temporal resolution and was not a practical tool for imaging dynamic systems. Recent improvements in spinning disk confocal microscopy and high-speed camera technology have made it a viable technique for imaging of microfluidic systems. By reconstructing thin planes of data, 3-D velocity profiles of the flow behavior of solid microparticles suspended in a flowing liquid medium are obtained. Results provide valuable information about particle flow behavior within microchannels, which can be used to properly design novel microfluidic devices.

Fluidic devices made in the micron size range offer significant advantages over their large-scale counterparts in fields such as medical diagnostics, pharmaceuticals, and security. These advantages include reducing the reagent used, throughput time, and cost, while increasing accuracy. A method for recording high speed, high sensitivity, and high-resolution images of particulate flow in a liquid medium through microchannels is necessary to enable control and design of novel microfluidic devices. This is critical to the design of microfluidic processes involving liquid-particulate interactions such as microreactions, particulate sampling, and blood flow.

Computational fluid dynamics is also used to simulate the 3D particulate flow in the micorchannel. Various fluid-particle and particle-particle interactive forces are considered, and the particle trajectories are solved using lagrangian method. Experimental and computational results for pressure driven, Poiseuille flow are presented and compared. A Confocal Micro-Particle Tracking (CM-PT) system with the ability to quantify 3-D multiphase fluid flows in microchannels is demonstrated.