Indexed on: 21 Jan '18Published on: 21 Jan '18Published in: Journal of Chromatography A
A new type of microfluidic flow distributor (referred to as the mixed mode or MM-distributor) is proposed. Its performance characteristics are determined using computational fluid dynamics (CFD), both in the absence and the presence of clogging, which is an important problem in microfluidic systems. A comparison is made with two existing, well-performing distributor types: the bifurcating (BF) distributor and an optimized diverging distributor, the so-called radially interconnected (RI) distributor. It was found that, in the absence of clogging, the MM-distributor produces only a little more dispersion than the bifurcating (BF) distributor, but much less than the radially interconnected (RI) distributor. The dispersion in an MM-distributor also follows a similar dependency on its width (power ≅ 2) as the BF-distributor. The dispersion in the RI-distributor on the other hand displays a very disadvantageous 4th-order dependency on its width, prohibiting its use to distribute the flow across wide beds (order of millimeters or centimeters). These observations hold independently of the flow rate. With increasing degree of clogging, the MM-distributor rapidly becomes advantageous over the BF-distributor, owing to the fluid contact zones that are provided after each bifurcation step. This means that overall, and when the occurrence of clogging cannot be excluded, the MM-type distributor seems to offer the best possible compromise between the ability to cope with local clogging events and the dispersion in the absence of clogging.