Dendrite growth under forced convection: analysis methods and experimental tests

An analysis is given of the nonisothermal growth of a dendrite crystal under forced fluid flow in a binary system. The theoretical model utilized employs a free moving crystal-liquid interface and makes use of the Oseen approximation for the equations of motion of the liquid. A criterion for the stable growth of two-dimensional and three-dimensional parabolic dendrites is derived under the assumption of an anisotropic surface tension at the crystal-liquid interface, which generalizes the previous known results for the stable growth of a dendrite with convection in a one-component fluid and for the growth of a dendrite in a two-component system at rest. The criterion obtained within the Oseen hydrodynamic approximation is extended to arbitrary Peclet numbers and dendrite growth with convection in a nonisothermal multicomponent system. Model predictions are compared with experimental data on crystal growth kinetics in droplets processed in electromagnetic and electrostatic leviation facilities. Theoretical and simulation methods currently being developed are applied to crystallization processes under earthly and reduced gravity conditions.