Coarsening dynamics in off-critically quenched binary systems under microgravity conditions

Effects of thermo-capillary motion of spherical droplets on the coarsening dynamics in off-critically quenched binary, systems are Studied by means of the droplet growth model for the case where the temperature gradient is imposed Under microgravity conditions. Such movement of precipitating droplets is driven by variations in interfacial tension Caused by the temperature gradient (the Marangoni effect), leading to instantaneous droplet coagulation events. Large-scale computer simulation results show that (I) even in the presence of Marangoni effect the average droplet radius grows in time with the growth exponent 1/3, and also the scaling regime for the droplet size distribution does exist. which are similar to those of the well-known Ostwald ripening process: and (2) effects of thermo-capillary motion induced coagulation result in enhanced coarsening rate and fairly broad scaling form of the size distribution function. compared with those of the Ostwald ripening. (C) 2002 Elsevier Science B.V. All rights reserved.