Effect of top and bottom blowing conditions on spitting in converter
Shota Amano, Shingo Sato, Yukio Takahashi, Naoki Kikuchi
Abstract
Abstract The effect of top blowing and bottom blowing conditions on spitting behavior was investigated by water model experiments and numerical calculation. The results of the water model experiment showed that reducing the jet velocity by using a larger nozzle diameter was effective for reducing spitting. The numerical calculation indicated that interference between the top blown gas jet and the bottom blowing plume increases the gas velocity at the rim of the cavity, causing heavier spitting. A new index using the geometrical locations of the neighboring cavity and plume was proposed. The spitting rate decreased under conditions with lower interference by avoiding interaction between the top blown gas jet and the bottom blowing plume. The energy distribution in the blowing process was discussed based on a water model experiment using bath mixing time, bath vibration, and the spitting rate. The energy for spitting was explained convincingly by the difference between the energy input and the energy of bath vibration, cavity formation, and bath mixing. The results implied lower interference of the top and bottom gas resulted in lower energy for spitting generation.