  A new comprehensive analysis of Stefan's flow caused by a free growing
droplet in vapor-gas atmosphere with several condensing components is
presented. This analysis, based on the nonstationary heat and material balance
and diffusion transport equations, shows the appearance of the Stefan inflow in
the vicinity of the growing droplet and the outflow at large distances from the
droplet as a consequence of nonisothermal condensation. For an ensemble of
droplets in the atmospheric cloud, this flow provides an increase of the total
volume of the cloud, which can be treated as cloud thermal expansion and leads
to floating the cloud as a whole due to buoyancy. We have formulated the
self-similar solutions of the nonstationary diffusion and heat conduction
equations for a growing multicomponent droplet and have derived analytical
expressions for the nonstationary velocity profile of Stefan's flow and the
expansion volume of the vapor-gas mixture around the growing droplet. To
illustrate the approach, we computed these quantities in the case of droplet of
stationary composition in air with several specific vapors
(${\mathrm{C_2H_5OH/H_2O}}$; ${\mathrm{H_2SO_4/H_2O}}$; ${\mathrm{H_2O}}$).
