BUBBLE AND LIQUID FLOW CHARACTERISTICS IN A WOODS METAL BATH STIRRED BY BOTTOM HELIUM GAS INJECTION

A model study was carried out to elucidate bubble and liquid flow char acteristics in the reactor of metals refining processes stirred by gas injection. Wood's metal with a melting temperature of 70 degrees C wa s used as the model of molten metal. Helium gas was injected into the bath through a centered single-hole bottom nozzle to form a vertical b ubbling jet along the centerline of the bath. The bubble characteristi cs specified by gas holdup, bubble frequency, and so on were measured using a two-needle electroresistivity probe, and the liquid flow chara cteristics, such as the axial and radial mean velocity components, wer e measured with a magnet probe. In the axial region far from the nozzl e exit, where the disintegration of rising bubbles takes place and the radial distribution of gas holdup follows a Gaussian distribution, th e axial mean velocity and turbulence components of liquid flow in the vertical direction are predicted approximately by empirical correlatio ns derived originally for a water-air system, although the physical pr operties of the two systems are significantly different from each othe r. Under these same conditions, those turbulent parameters in high-tem perature metals refining processes should thus be accurately predicted by the same empirical correlations.