CFD-based modeling of the hydrodynamic production process of polymeric microfibers and an experimental evaluation

Previously, we have developed methods to continuously fabricate polymeric microfibers via micro-scale hydrodynamic phenomena and 'on the fly' photo-polymerization. For the production of microfibers. with desired diameters by regulating the sample and sheath flow rate, an appropriate numerical model is required so that the laborious trial-and-error process that characterizes the search for optimal production conditions can be minimized. In this paper, a CFD-based model of the hydrodynamic process is developed. We employed commercially available CFX-5.7 as a CFD tool. An evaluation of the established model was carried out with regard to variation of the flow conditions and the viscosity. First, the simulated sample flow patterns in the sheath flow are obtained and their qualitative and quantitative shapes are similar to the experimentally acquired ones. Second, the diameters of the microfiber under various flow conditions were measured from the CFD model and experiment. An improvement in the prediction of the fibers' diameter (40% improvement at a 2.4 μ1 min^-1 sample flow rate compared with the analytical results) was found. The effect of other parameters such as the viscosity of the sample and sheath flow was also investigated using the CFD-based simulation model.