(140g) Analytical and Experimental Studies of Mass Transfer and Separation of Species in a Wavy-Walled Tube by Imposed Fluid Oscillation

Oscillatory flows in tubes have shown to greatly be used as a novel way to increase the separation of two diluted species present in a carrier and provide a high throughput or mass transfer. This will aid, for example, in long-manned space exploration, to mechanically separate trace contaminants from air without a re-supply or regeneration of materials. The separation is connected to dispersion where naturally slow diffusing species is axially dispersed down a tube to greater extent than a naturally faster diffusing species. Given the story of oscillatory flow in a tube, it is evident that the flow profiles generated by the oscillatory system directly influence the movement of species. Therefore, having a wavy-walled configuration would have a marked effect on the flow field, which will in turn affect the mass transfer and separation.

We present analytical and experimental studies of the wavy-walled tube geometry for a pressure driven configuration where an oscillating piston produces the oscillating flow profiles. The pressure driven configuration causes the flow to produce regions of recirculations within the recesses of the boundary that trap individual species thereby hindering its transport along the tube and affect the overall throughput or mass transfer. In order to validate the analytical model with experiment, we consider a mixture of carbon dioxide and methane with nitrogen as a carrier gas. Our preliminary experimental results show qualitative agreement with the analytical model. Both analytical and experimental studies suggested that the relative transport between carbon dioxide and methane present in nitrogen (a carrier gas), the wavy-walled tubes favors carbon dioxide. Oscillating flows in wavy-walled tubes can potentially provide a large separation due to the flow recirculations.