(189f) CFD Modeling of a Massively Arrayed Fiber Reactor

The computational fluid dynamics (CFD) modeling of a static multiphase fluid reactor is described in this work. These reactors are packed with upwards of tens of thousands of fibers, and the fluid phase flows in a microfluidic environment around those fibers, massively arrayed. The geometry might be thought of simply as a microfluidic flow, annular, around the fiber. Annular microfluidic flows are not well described in the literature, nor how that might upscale to a massive array where the channels have the potential for turbulence between them. Yet these separators are commercially available, and well understood to be effective continuous systems to break or prevent emulsions while providing excellent high multiphase surface area for mass transfer to occur. Microfluidic flows are a well-researched subject, although the majority deal solely with single channels whereas the fiber reactor (FR) platform can be said to comprise thousands of channels. The computational modelling of microfluidic flows in single micro channels have been done in many studies and we reproduced a recent study in literature in order to validate our programing method. However, no CFD study has specifically attempted to model the flows in the massively arrayed channels that make up a FR. The aim of this research is to model the fluid dynamics and subsequently mass transfer performance of two-phase immiscible flows in the FR. Achieving the CFD model of a FR is challenging because the geometry comprises of channels packed with micron-sized rigid fibers. Hence, we present results of modelling flow around a single fiber using symmetry boundary conditions. We compare the results to a model geometry comprising four fibers using symmetry conditions. Under reported parameters, the phase distribution develops as a plugs of dispersed phase in the continuous phase similar to computational models in single channels without injection conditions. Phase structure in the four fiber model is shown and compared to the phase structure around a single fiber. Results are presented showing the effects of the channel wall wettability (contact angle), total flow rates (dispersed and continuous), flow rate ratio and interfacial tension on the equivalent droplet diameter of dispersed phase, slug length of dispersed phase, and specific area of the dispersed phase.