Effect of physical properties of dispersed phase on the residence time distribution in straight capillaries

In the present work, the effect of dispersed phase properties on the RTD in two-phase flows was studied. The experiments were carried out using six different dispersed phases at a variety of flow rates at low Re. Although it was shown that the properties do not directly affect the nature of distribution, it affects the slug lengths and film thickness depending on the dispersed phase used, which in turn affects the overall nature of the distribution. It was also observed that with increasing viscosity as the extent of internal recirculation decreases significantly, the dispersion coefficient also decreases. A modified dispersion model that takes into account the back-mixing of the tracer through the film region through a leakage factor is reported. The model was validated using experimental data for chloroform-water system over a range of flow rates and also for other systems. The thread and knot based multi-parameter model can further be extended to various multi-phase flows operating under laminar conditions. © 2020 Elsevier Ltd