Microchannel flow of a macromolecular suspension

In the delivery of DNA molecules by microfluidic devices, the channel width is very often in the same order as the size of the DNA molecules and the applicability of continuum mechanics at this level may be questioned. In this paper we use finitely extendable nonlinear elastic (FENE) chains to model the DNA molecules and employ the dissipative particle dynamics (DPD) method to simulate their behavior in the flow. Simple DPD fluids are found to behave just like a Newtonian fluid in Poiseuille flow. However, the velocity profiles of FENE chain suspensions can be fitted with power-law curves, especially for dilute suspensions. Some results on the conformation and migration of FENE chains are also reported.