Computational Fluid Dynamic (CFD) analysis to mitigate design challenges in Centrifugal Microfluidic Platforms

A. Gupta, R. Castillo, K. Ramaswamy
Flow Science, Inc.,
United States

Keywords: centrifugal platform, computational fluid dynamics, lab-on-a-disc, fluid-air interface, microfluidics

Summary:

For over a decade, Compact Discs (CDs) have shown tremendous potential in rapid immunoassaying and clinical biochemistry for blood diagnostics. For instance, they can be used as micro total analysis systems (μTAS) in which several individual assays are embedded and run simultaneously on a single chip. A primary concern in the design of such devices, however, is the radial unidirectionality of the flow due to centrifugal forces on the disc as well as the resultant spatial constraints that limit the number of analytical components in a μTAS. A potential solution was proposed by Gorkin et al (2010) where the authors used the energy stored due to pneumatic pumping to overcome flow unidirectionality in a centrifugal microfluidic platform. The amount of energy stored depends, among other factors, on the microchannel configuration, the rotational velocity of the platform as well as fluid/gas properties. In this study, we use a Computational Fluid Dynamic (CFD) model to study the effects of rotational velocity on the storage and release of pneumatic energy in a centrifugal platform. Different approaches in handling the fluid-gas interface are compared and the resultant propulsion of fluid towards the center of the platform is analyzed. The CFD model was validated over a range of angular velocities and the results indicate that numerical modeling can be a promising tool in the design of centrifugal microfluidic platforms. References: Gorkin, R., Clime, L., Madou, M. et al. Pneumatic pumping in centrifugal microfluidic platforms. Microfluid Nanofluid 9, 541–549 (2010). https://doi.org/10.1007/s10404-010-0571-x