Taylor dispersion of a solute in a microfluidic channel

The dispersion of a solute, traveling in a laminar-flow microfluidic channel, along the major axis of the channel is described by Taylor dispersion. It is shown that although diffusion of solute along the major axis is often neglected in constructing a governing transport equation, axial dispersion due to the laminar flow profile influences the distribution of solute in the channel. An expression for the effective Taylor dispersion coefficient due to the laminar velocity profile is derived and verified by comparing the predicted dispersion to results from a three-dimensional finite-element representation of the fluid dynamics and solute transport. Since the dispersion coefficient can be several orders of magnitude greater than the molecular diffusion coefficient, axial dispersion in microfluidic channels should not be casually neglected. (C) 2001 American Institute of Physics.