Analysis of mass transfer between a sequence of drops and a surroundings gas

Mass transfer between a sequence of monodisperse droplets and a surrounding gas is theoretically analyzed for two mass transfer processes: (i) evaporation of drops into a laminar gas flow and (ii) the uptake of a soluble component from the flowing gas. The evaporation process is modeled as a line (or rod) source of vapor located at the axis of the droplet array, and the vapor concentration distribution in the gas phase is obtained by numerically solving the convective diffusion equation. To model the uptake of trace gases, the equation of continuity is solved for both the liquid and gas phases, and the fluxes are matched at the gas/liquid interface. A numerical solution is presented for the gas uptake by the drops which can be applied to interpret experimental data, and the analysis is applied to the absorption of HCl and SO2 by water droplets.