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Publication Citation: Droplet Formation at Microfluidic T-junctions

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Author(s): David A. LaVan; Xiang Xu;
Title: Droplet Formation at Microfluidic T-junctions
Published: December 31, 2008
Abstract: Analysis of droplet formation in microfluidic systems is important to understand the operation of these devices, and to permit optimal design and process control. Droplet formation in microfluidic T-junction devices was studied using experimental and numerical methods. The simulations agree well with experimental data from PDMS devices; they show that droplet pinch-off is controlled not by viscous stress, but rather caused by pressure buildup after channel blocking due to the second phase. The period of droplet formation is dependent on velocity of the flow, but not viscosity or interface tension of the fluids. Analysis using dimensionless period, which is equivalent to dimensionless droplet length, shows that dimensionless period is controlled primarily by water fraction but is also dependent on velocity following a power-law relationship. Higher values of capillary number tend to extend the distance for droplet pinch-off. Droplet length does depend on flow velocity at low velocities, but reaches a relatively constant length at higher flow velocities. The coefficient of variation of droplet volume/length increases with increasing capillary number.
Conference: 2008 Materials Research Society Fall Meeting
Proceedings: Microelectromechanical SystemsýMaterials and Devices II
Pages: 6 pp.
Location: Boston, MA
Dates: November 30-December 4, 2008
Keywords: MEMS; microfluidic; finite element modeling; droplet; bioMEMS; two-phase flow
Research Areas: Microfluidics, Modeling
PDF version: PDF Document Click here to retrieve PDF version of paper (280KB)