Numerical simulation of surface tension induced melt-layer movement after disruption load

AbstractSome stainless steels have wavy resolidification surface after a simulated plasma disruption. The rough surface is considered to be formed bym ovement of the melt layer, which is driven by imbalance of the surface tension. The effect occurs when the temperature coefficient of the surface tension is positive. The temperature of the melt of an elevated part is high, hence its high surface tension draws melted material away from other locations resulting in growth of the swell. A computer code was developed for simulating the phenomenon. The heat-conduction equation was solved to obtained the position of the liquid-solid interface, and the velocity profile was calculated from equilibrium of the surface tension and the viscous resistance, neglecting inertial force. The mass transfer in the direction parallel to the surface was computed and then the changes of the shape of the surface was calculated using the mass conservation law. The calculational result for the roughness, the dominant wavelength of undulation and their dependence on the heat load agreed well with the experimental result, which indicates the validity of the above mechanism of rough-surface formation.