The present study aims at investigating the deformation mechanism of liquid-liquid interfaces by both the experimental and numerical approaches. The experiments reveal that the topology of an initial flat interface composed of a Newtonian aqueous and a Newtonian oil phases can be modulated as climbing or descending along a rotating rod according to the ratio of the kinematic viscosity between these two liquid phases. The measurements of the fluid flow fields by PIV highlight the relationship between the appearance of the Taylor-Couette instability in the less viscous phase and the interface's orientation. The increasing rod rotation speed expands the Taylor-Couette vortices, and intensifies then the magnitude of the interface deformation.The numerical simulation by the VOF method is in qualitative agreement with the experimental results, in particular the interface shape and the qualitative influence of different parameters, even under very high rotation speeds of the rod.

-The gas-liquid two-phase mass transfer process in microchannels is complicated due to the special dynamical characteristics. In this work, a novel method was explored to measure the liquid side volumetric mass transfer coefficient k L a. Pressure transducers were utilized to measure the pressure variation of upward gas-liquid two-phase flow in three vertical rectangular microchannels and the liquid side volumetric mass transfer coefficient k L a was calculated through the Pressure-Volume-Temperature correlation of the gas phase. Carbon dioxide-water, carbon dioxide-ethanol and carbon dioxide-n-propanol were used as working fluids, respectively. The dimensions of the microchannels were 40 μm×240 μm (depth×width), 100 μm×800 μm and 100 μm×2000 μm, respectively. Results showed that the channel diameter and the capillary number influence k L a remarkably and that the maximum value of k L a occurs in the annular flow regime. A new correlation of k L a was proposed based on the Sherwood number, Schmidt number and the capillary number. The predicted values of k L a agreed well with the experimental data.