Since microfabrication techniques are typically planar processes, microchannel flows typically have significant predevelopment due to the upstream reservoir having the same height as the microchannel. The main concerns of the current study are categorized into finding the effects of typical microchannel geometry on the velocity entrance length in the laminar flow regime and providing the turbulence transitional Reynolds number range using the details of the velocity profile rather than global measurements of pressure drop. A rectangular micro-channel of aspect ratio ∼2.65 and the hydraulic diameter 380μm was used in this study. Micro particle image velocimetry measurement was performed to measure the velocity profiles. The entrance length is reduced about 45% and the transitional velocity profile is measured at Re=2900. The velocity profiles do not show deviation from the fully developed laminar flow profiles up to Re=2100. Related to the flow transition, the close resemblance between the correlation function peak broadening and the turbulence intensity is observed.

This content is only available via PDF.
You do not currently have access to this content.