MOMENTUM AND MASS-TRANSFER IN SUPERSATURATED SOLUTIONS AND CRYSTAL-GROWTH FROM SOLUTION

The physical properties of supersaturated solutions such as solution d ensity rho, shear viscosity eta and solute diffusivity D are strongly dependent on solute concentration c(infinity): rho = rho(C-infinity), eta = eta(C-infinity) and D = D(c(infinity)). The concentration depend ence of the properties has been taken into account in the rederivation of the generalized momentum and mass transport equations governing cr ystal growth from solutions. The non-linear ordinary differential equa tions obtained for the steady regime of isothermal crystal growth were analyzed. The exact simultaneous solutions obtained for the rederived transport equations resulted in the following conclusions: (a) There exists a restriction imposed on the Schmidt number for supersaturated solutions: Sc-infinity much greater than 4/9. only under this restrict ion the generalized momentum and mass transfer equations have simultan eous consistent solutions. (b) The solution-crystal interface profile ''thickness'' delta(int)(x(1)) is proportional to the diffusion bounda ry layer (DBL) thickness: delta(int)(x(1)) approximate to 0.24 delta(d iff)(x(1)). (c) The ratio of solute flux along the solution-crystal in terface to the flux along the DBL edge is the increasing function of a nd is dependent only on Sc-infinity.