Affiliations: Department of Chemical and Process Engineering,
University of Sheffield, Mappin Street, Sheffield S1 3JD UK. on leave from CVUT
- Czech Technical University, Prague, Czech Republic.
Abstract: Fluidics is a technology of generating and controlling fluid flows -
preferably without the action of mechanical moving components. Microfluidics
perform these tasks in small, typically micron-sized structures. Essential part
of almost all microfluidic systems are flow control valves. The basic problem
is the low Reynolds number Re: inertial effects used in large-scale fluidics
are too small relative to viscous dissipation. New approaches, such as pressure
or electrokinetic driving are required. In the subdynamic, viscosity dominated
flow regime, Re ceases to be of importance and for pressure-driven valves a new
characterisation number was to be introduced. An example of a diverter valve,
developed by the author, is described and the meaning of the new dimensionless
parameter is demonstrated.
Keywords: flow control, valves, fluidics, microfluidics, microvalves, Reynolds number