Experimental Investigation of Micro-Channel Blockage Phenomena
Yamaguchi, Eiichiro
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https://hdl.handle.net/2142/87734
Description
Title
Experimental Investigation of Micro-Channel Blockage Phenomena
Author(s)
Yamaguchi, Eiichiro
Issue Date
2005
Doctoral Committee Chair(s)
Adrian, Ronald J.
Department of Study
Theoretical and Applied Mechanics
Discipline
Theoretical and Applied Mechanics
Degree Granting Institution
University of Illinois at Urbana-Champaign
Degree Name
Ph.D.
Degree Level
Dissertation
Keyword(s)
Engineering, Mechanical
Language
eng
Abstract
An experimental investigation of blockage and a study of fluid and particle motion within micro-channels having a variety of cross-sectional geometries have been conducted over a wide range of flow conditions. A micro-channel can be blocked by particles in dilute particle-laden fluid, if they have a relatively high particle-to-channel diameter ratio with very high Peclet number. It is shown that blockage is triggered by a shear-induced arching formation, which does not require any flocculation prior to the arching formation. The experimentally determined non-dimensional scaling parameters from micro-glass capillary experiments suggest that the probability of blockage can be scaled by a combination of the Stokes number, the diameter ratio, the channel diameter to length ratio, and the number of the particles passed through the channel. Here, the Stokes number can be expressed as a combination of the Reynolds number, density ratio, and the diameter ratio. The scaling parameter fits the theoretical description of the shear-induced arching mechanism very well, since the mechanism can be explained as a combined effect of channel-to-particle geometry and particle dynamics in the shear flow. An examination of the blockage position suggests that an exceptionally high percentage of blockages happen at the inlet of the channel. To investigate the particle motion at the channel inlet, micro-PIV measurements and visualization of the particle trajectories have been conducted with newly developed micro-fluidic devices that allow us to perform multiple optical diagnostics in complex geometries. The results of the flow-particle visualization in the micro-channels indicate that collision of particles against the channel wall increases the collision rate of particles. For the inlet flow, collision frequency and angle are determined by the angle of contraction.
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