Modeling of a Bubble-Train Flow and Interphase Mass Transfer In a Long Microchannel

A model of a bubble train flow, accompanied with mass transfer, in a lengthy capillary tube is developed. In contrast to models presented in literature, our modeling approach accounts for expansion of gas bubbles and flow velocity increase along the channel due to the pressure drop caused by friction losses. The model performance is illustrated by a number of computational examples. The distributions of the bubble velocity and the volumetric mass transfer coefficient along the channels of different diameters are presented. The deviation of the dissolved gas concentration from the saturation concentration along the channel is used as a characteristic of closeness of a fluid system to the phase equilibrium. The calculations explicitly demonstrate that the deviations of gas-liquid mixture flows from equilibrium in lengthy capillary channels of small diameters are small (see Figure below). The effect of the channel diameter, the channel length and the bubble nucleation frequency on the deviation of the system from equilibrium is also studied.