A numerical insight of the residence time distribution in multiorifice baffled tubes

Résumé

In the present work, the fluid flow and the transport of species in an intensified topology of oscillatorybaffled reactors is analyzed here by means of Computational Fluid Dynamics. The classic configurationwith equidistant single orifice plate baffles has been replaced by multiple-hole disk, of the same totalcross-sectional area. The flow through these disks generates an array of parallel jets downstream andupstream (depending upon the phase of the oscillatory flow), exhibiting various swirl structures thatincrease the radial mixing.Time-dependent flow patterns are presented here for configurations of disk with 1, 3, 7, 19 and 43orifices in a 25 mm diameter tube. The evaluation of their mixing performance has been accomplishedby injecting a pulse of tracer which is conveyed to the end of the tube by the compound effect of the netflow rate and the oscillations. The influence of the oscillation amplitude was analyzed a constantfrequency of f=0.35 Hz. The concentration-time profile of the tracer throughout the reactor was analyzed.Results show an important enhancement of plug flow behavior and mixing performance by increasingnumber of orifices.