ИСТИНА

In this work, the regularities of spatial flows and mass transfer in supersaturated water-salt solutions during a number of crystal growth (potassium dihydrogen phosphate crystal – KDP [1] and mixed nickel-cobalt crystal – KCNSH [2]) has been numerical modeled. The solution flow occurs in a region of complex shape containing solid crystallizing bodies, the growth of which is determined by the conditions of their flow around (by the velocity and direction of flow around and the salt saturation and temperature of the solution). Two variants of the solution inflow into the crystallizer are considered: in the first, the solution inflows in the central region, and in the second, the solution flows peripherally along the perimeter of the crystallizer. Both cases are considered in laminar regimes at Reynolds numbers significantly lower than the critical ones. Moreover, the crystallizers sizes were increased and the flow around corresponded to the large Reynolds number and turbulent flow around. Therefore, for numerical simulation, averaged Navier-Stokes equations were used in the form of a “standard” (k−ε) turbulence model. The crystal growth process is considered in a conjugate formulation as mass transfer in the "solution-crystal" system. It is shown, how local features of hydrodynamics and mass transfer near a growing crystal surface specifically affect on the local crystal growth rate and defect formation.