An electrochemical method to detect flow profiles during convection in liquid metals

A solid-state electrochemical method for flow visualization was developed t o investigate the orientation of flow due to natural convection in semicond uctor melts. The experiment was conducted in a right cylindrical ampoule ma de from recrystallized alumina and heated in a Bridgman furnace. Multiple s olid-state electrochemical cells/sensors that were electrically insulated f rom one another were incorporated along the periphery of the ampoule. Liqui d tin that was subject to temperature gradients was used as the model fluid to represent a high-temperature, opaque melt. Atomic oxygen was used as a tracer species, which could be potentiostatically injected or extracted loc ally at one of the sensors and monitored at the other cell locations on the melt/electrolyte boundaries in the galvanic mode as a function of time. Va rious convective flow patterns were inferred from these results for differe nt aspect ratios of the melt and for different imposed temperature gradient s. The experimental results were shown to agree qualitatively with numerica l predictions. (C) 1999 Elsevier Science B.V. AU rights reserved.