MEASUREMENTS OF BUBBLE PLUME BEHAVIOR AND FLOW VELOCITY IN GAS-STIRRED LIQUID WOODS METAL WITH AN ECCENTRIC NOZZLE POSITION

The distribution of gas fraction and the flow field of gas-stirred liq uid metal in steel ladles at eccentric injection of the stirring gas t hrough the bottom of the vessel were measured in melts of 437 kg liqui d Wood's metal. The melts had a temperature of 100-degrees-C. The bath height was 37 cm and the vessel diameter 40 cm. The blowing nozzle wa s positioned at half of the vessel radius. Gas flow rates were between 100 and 800 cm3(STP)/s. The gas fractions were measured by electrical resistance probes. The flow velocity of the liquid metal was determin ed by magnet-probes. The gas fraction and the velocity distribution in the plume were found to have a Gaussian shape. The cross-section of t he plume is ellipsoid, as the plume width in the direction of the radi us was a little smaller than the width in the direction perpendicular to it. Moreover the plume was inclined to the wall. The results which were found for the plume are mathematically described. The flow field at eccentric gas-stirring consists of one great loop, which fills almo st the entire vessel. This is contrary to centric blowing, where for a spect ratios of the ladle in the order of 1, a toroid is formed in the upper and a dead zone exists in the lower part of the vessel. The con sequences of this behaviour, especially for mixing in the melt, are di scussed.