Solutal convection during directional solidification

摘要: During directional solidification of a binary alloy at constant velocity, buoyancy-driven fluid flow may occur due to the solute gradients generated by process. Numerical calculations and fields in melt have been carried out using finite differences two-dimensional, time-dependent model that assumes planar crystal-melt interface allows gravitational accelerations. The container walls are rigid perfectly insulating for solute. For vertical accelerations, as solutal Rayleigh number is varied, multiple steady states occur. bifurcation from quiescent state be subcritical or transcritical, depending on aspect ratio container. Calculations also performed acceleration assumed uniform magnitude with its direction rotating uniformly. results obtained Schmidt 10 0.0001 G. maximum variation concentration calculated various values rotation rate acceleration.