Shalliker R A, Wong V, Guiochon G
Nanoscale Organisation and Dynamics Group, University of Western Sydney, South Penrith D.C. 1797, Australia.
J Chromatogr A. 2007 Aug 17;1161(1-2):121-31. doi: 10.1016/j.chroma.2007.05.040. Epub 2007 May 17.
The complex pattern of viscous fingering (VF) appears to be chaotic. Its early evolution seems predictable but, on a long time-scale, it is not so and the transition is complex. Detailed experimental observations of fingering systems have been hindered by various limitations. We present a new method for visualising VF in particulate beds. Our results show that the onset of VF and its initial evolution are reasonably reproducible at very low Reynolds numbers (Re < 0.005). The transition to irreproducibility of the fingering pattern develops progressively over long migration distances. When the flow velocity increases, changes in the finger distribution take place over shorter migration distances, become more important, and the fingers evolve faster. Understanding this new aspect might allow improvements in the efficiency of processes governed by VF, e.g. injection of large, concentrated samples or transfer of large fractions between two streams having different viscosities.
粘性指进（VF）的复杂模式似乎是混沌的。其早期演变看似可预测，但从长期来看并非如此，而且这种转变很复杂。指进系统的详细实验观测受到各种限制。我们提出了一种在颗粒床中可视化VF的新方法。我们的结果表明，在非常低的雷诺数（Re < 0.005）下，VF的起始及其初始演变具有合理的可重复性。指进模式向不可重复性的转变在长迁移距离上逐渐发展。当流速增加时，指状物分布的变化在较短的迁移距离上发生，变得更加重要，并且指状物演变得更快。理解这一新方面可能会提高由VF控制的过程的效率，例如注入大量浓缩样品或在具有不同粘度的两股流之间转移大部分物质。
