Viscous fingering in packed chromatographic columns: Non-linear dynamics

Viscous fingering (VF) is a hydrodynamic instability that occurs in a chromatographic column when a less viscous fluid displaces another more viscous one. This instability is detrimental to separation techniques as it leads to distorted peaks and peak broadening. Nonlinear interactions between developing fingers lead to complex dynamics investigated in the present study by means of numerical simulations based on a simple model for miscible VF of finite samples. We review the properties of nonlinear VF and discuss the quantitative measures that can be applied both on such numerical as well as on experimental data to gain insight into the influence of the parameters of the problem on the nonlinear properties of the fingers and on the broadening of output peaks.

► Viscous fingering leads to distorted peaks and peak broadening.
► Variances of concentration distributions provide information on viscous fingering.
► Broadening of peaks due to viscous fingering increases slightly with flow velocity.
► Fingering effects decrease with increasing ratio of transverse and axial dispersion.