Temperature fluctuations of the Marangoni flow in a liquid bridge of molten silicon under microgravity on board the TR-IA-4 rocket

Temperature fluctuation measurements in a liquid bridge of molten silicon, which shows the Marangoni flow in highly super-critical condition, are performed in a half-zone configuration under microgravity on board a TR-IA-4 rocket and on the ground, In the microgravity experiment, two types of temperature oscillation are observed during the melting process of silicon and in the cylindrical half-zone melt. The former oscillation; which has a frequency of about 0.1 Hz during the melting process, has an antiphase correlation of temperature oscillation measured in thermocouples separated by 90 degrees azimuthal angles, The latter oscillation in the cylindrical liquid bridge has no remarkable frequency; however, it tends to have the antiphase correlation in between thermocouples with 180 degrees azimuthal angles. In the ground experiment, temperature fluctuations have a characteristic frequency of 0.2 Hz and there is an antiphase correlation of temperatures in thermocouples with 180 degrees azimuthal angles by using the slender melt zone. (C) 1998 Elsevier Science B.V. All rights reserved.