CONTINUOUS MEASUREMENTS OF BUBBLE CHARACTERISTICS IN A MOLTEN IRON BATH WITH AR GAS INJECTION

Present authours developed a new electro-resistivity probe being able to continuously measure bubble characteristics in a molten iron bath agitated by gas injection. The life of the probe was about two hours at a bath temperature of 1 250 degrees C. The axial and radial distributions of gas holdup alpha, bubble frequency f(B), mean bubble rising velocity (u) over bar(B) and mean bubble diameter (d) over bar(B) were determined for the Ar gas flow rates of 50 and 100 cm(3)/s (at 1 250 degrees C). The Ar gas was preheated up to 1 250 degrees C and then injected through a single-hole centric bottom nozzle. The results were compared with empirical correlations derived from cold and hot model experiments. The measured values of alpha, f(B) and (u) over bar(B) in the upper part of the bath were approximated satisfactorily by correlations proposed by the present authors, but they did not agree with the experimental results of Kawakami et al. The measured values of (d) over bar(B) were a little smaller than predicted values by Sano et al. and Irons et al.