(251l) Dynamic Modeling of Fluid Flow Fractionation Under Couette and Poiseuille Flows

Parameters such as effective velocity and effective diffusivity capture the efficiency of species separation. The study of how different physical conditions affect these parameters is relevant. The effects of orthogonal fields and radius ratios on the effective parameters were analyzed and developed in a previous effort (Dueck, Oyanader & Oyanader, 2015). These equations can be implemented in the development of a concentration profile of a solute within a cylindrical and/or rectangular cell system. It is traditional that the dynamic concentration profile in a typical FFF cell was modeled using the Dirac delta function in the representation of the solute injection, giving it an initial concentration value that infinite. This function is often used to simplify pulse like mathematical equations, but did not accurately embody the actual behavior of the system.

The equation for the dynamic behavior of the concentration of species is modelled omitting the use of the Dirac delta function but including a forcing step expression. The new equation represents more realistically the phenomena and the results of a pulse injection of solute into the system. Six main variables affecting the separation process were investigated. To close, the results and conclusions derived from this study will be highlighted to illustrate the modeling technique as well as the system behavior.