The impact of flow distribution on column performance: A computational fluid dynamics study

• We measured the effect of flow distributors and collectors on column performance.
• We studied a generic design to give broad insights.
• Flow distributors and collectors do impact the band shape and variance.
• The impact on state of the art separations is minimal.
• Distributor design can become important with increasing column performance.

In this manuscript, the band broadening contribution of a generic flow distributor and collector has been calculated using computational fluid dynamics (CFD). The effects of distributor design and operating conditions on distributor performance have been studied. The non uniform flow fields in the distributor cause band deformation and an increase in volumetric band variance (σv2). This volumetric band variance was calculated to be about 0.2 μl2 at the inlet of a 4.6 mm ID column and 0.3 μl2 at the outlet for a flow rate of 2 ml/min. For a 2.1 mm column the volumetric band variance is about 0.002 μl2 for a flow rate of 0.41 ml/min. For current column performance the measured contributions are negligible in practice, probably because designs have been empirically improved together with improving column performance. None the less, the simulations show that bad distributor design can be detrimental for column performance.