(602b) 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.