Author(s)

William J. Federspiel, Isabella Valenti

Medical Devices Laboratory, McGowan Institute for Regenerative Medicine, University of Pittsburgh.
Medical Devices Laboratory, McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, USA.

Soft and hard micromachining techniques used to develop microfluidic devices can yield microchannels of many different cross-sectional profiles. For semi-circular microchannels, these techniques often produce only partialsemicircular (PSC) cross-sections. This study investigated fully developed laminar flow in PSC microchannels as a function of a circularity index, κ, defined as the ratio of the radiuses along the curved and flat surfaces of the PSC profile. A correction factor, K, to the Hagen-Poiseuille relation was determined and was well-fitted by the power-law relationship K=5.299/κ^2.56. Actual correction factors were compared to estimates based on several hydraulic models for flow in microchannels of arbitrary cross-section, as well as the half-ellipsoid cross-section. The level of wall shear stress, when normalized by the pressure drop per unit length, increased approximately linearly with increase in the circularity index, κ.

Hagen-Poiseuille Flow; Poiseuille Flow; Flow Resistance; Wall Shear Stress

W. Federspiel and I. Valenti, "On Laminar Flow in Microfabricated Channels with Partial Semi-Circular Profiles," Open Journal of Applied Sciences, Vol. 2 No. 1, 2012, pp. 28-34. doi: 10.4236/ojapps.2012.21003.