Observation of Periodic Marangoni Convection in a Molten Silicon Bridge

Abstract

Marangoni convection of silicon melt was studied from the viewpoint of a heat and mass transfer for a low Prandtl number liquid. Temperature measurement and flow visualization in a half-zone bridge of molten silicon were carried out in a microgravity condition using the NASDA TR-IA-6 rocket. Fourier-transformation analysis of temperature fluctuations showed several peak frequencies for the microgravity condition when a temperature difference between interfaces of the bridge was 47.0 K. On the other hand, a single peak was seen when the temperature difference was 32.5 Kin the ground-base experiment. It is thought from those analyses that the transition from non-periodic to periodic flow of the silicon Marangoni convection in a half-zone liquid bridge system exists between these conditions. With using X-ray radiography, tracer motions in the azimuthal directions were observed near the molten silicon surface. This observation indicates that the tracer motions are driven by the temperature fluctuations in the azimuthal direction.