Title

Study Of The Backward Facing Step Flow Problem In Microchannels Using Micro Particle Image Velocimetry

Abstract

Flow at a backward facing step feature (1:5 expansion ratio) in a microchannel has been studied using micro particle image velocimetry (μPIV). The onset and development of a recirculation flow was studied as a function of flow rate. This flow pattern was further used to investigate two major parameters affecting μPIV measurements; the depth-of-focus and recording time-intervals between images in a μPIV double-frame. The onset of recirculation was initiated at flowrates that correspond to Reynolds numbers, Re>95, which is well beyond the typical working range of microfluidic devices (Re=0.01-10). The recirculation flow has a 3D structure due to the dimensions of the microchannel and the effect of no slip condition on the walls. The cross correlation algorithm used for deriving velocity fields from μPIV recordings was found not to be sensitive to variation of depth-of-focus and output flow fields were similar as long as the overall optical focus remained within the upper and lower bounds of the microchannel. However, variation of time intervals between images in a μPIV pair resulted in quantitatively and qualitatively different flow patterns for a given constant flowrate and depth-of-focus. Copyright © 2009 by the American Institute of Aeronautics and Astronautics, Inc.

Publication Date

12-1-2009

Publication Title

47th AIAA Aerospace Sciences Meeting including the New Horizons Forum and Aerospace Exposition

Number of Pages

-

Document Type

Article; Proceedings Paper

Personal Identifier

scopus

Socpus ID

78549285267 (Scopus)

Source API URL

https://api.elsevier.com/content/abstract/scopus_id/78549285267

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