Intensification of mass transfer from liquid to capillary wall by Taylor vortices in minichannels, bubble velocity and pressure drop

Hydrodynamics and mass transfer of slug flow in horizontal capillaries with different inner diameter (0.92 mm for hydrodynamics, 1.70 mm, 1.86 mm, and 2.53 mm for mass transfer) in water-air and glycerol-air (water-air-solid and glycerol-air-solid for mass transfer) systems were studied. Experimental data of bubble velocity and pressure drop was compared with values calculated by mathematical model of slug flow in capillaries proposed earlier. A simple equation to calculate the gas bubble velocity was obtained. The intensification of mass transfer in slug flow regime at the expense of the Taylor circulation was demonstrated experimentally. Semi-empirical formula for Sherwood number in a wide range of capillary number was obtained. (C) 2012 Elsevier Ltd. All rights reserved.