Elimination of the Back-attack Phenomenon on a Bottom Blowing Tuyere Investigated in Model Experiments

Abstract

Elimination of the back-attack phenomenon in the submerged gas jet, that is expected to decrease the erosion of bottom blowing tuyeres, was investigated in the water model and in the hot iron model. And the following results were obtained.
1)The back-attack phenomenon causes concave erosion in tuyere refractory.
2) The sum of impact pressure by the back-attack of a circular tuyere decreased beyond 19.6 bar ( 20 kg/cm²), and the frequency of that in a slit-shaped tuyere disappeared when the circumference ratio was greater than 3 in the water model.
3)The back-attack of a circular tuyere was observed in the hot iron model, and it was confirmed that the slit-shaped tuyere with the circumference ratio larger than 5 could eliminate the phenomenon completely.