ON MODELING OF MARANGONI CONVECTION FLOWS IN SIMULATED PLASMA DISRUPTIONS

Plasma disruptions in a fusion reactor will lead to high energy depositions for short times, which may cause melting of the wall. A comprehensive two dimensional transient computer model has been developed, which predicts the depth and motion of the molten layer in small beam simulation experiments. The model entails the solution of the Navier-Stokes equations coupled with the energy equation. The moving boundary technique was incorporated at the solid-melt interface for determining the shape and depths of the molten layers and at the free surface for evaluating evaporation rates. In the small scale hydrodynamics involved in the phenomenon and with high surface tension (metallic) substances. Marangoni convection flow plays an important role. It is demonstrated that impurities, through their effect on surface tension, exercise a determining influence in the flow intensities and resulting depth of the molten layer.