Shabnam Sabah

Splash Distribution in Oxygen Steelmaking

The study of splashing is important in understanding oxygen steelmaking. Splashing creates large interfacial area between reacting surfaces and thereby directly affects the kinetics of steelmaking reactions. In the present cold modeling work, a study of splashing has been carried out for various lance heights and gas flow rates. Sampling of droplets has been done in both radial positions and vertical positions across the bath to investigate the effect of sampling positions in estimation of the droplet generation rate. A novel approach has been developed to estimate the droplet generation rate. The results of the study have been compared with previous investigations. Results show that positioning of sampling is a critical issue and can affect the estimation of droplets present in the emulsion. This study also demonstrates quantitatively how much the droplet generation rate is reduced when the cavity mode changes from splashing to penetrating for different Blowing numbers.

Study of cavity modes in BOF by analysis of sound

Various cavity modes (i.e. dimpling, splashing and penetrating) are important phenomena in estimating splashing in oxygen steelmaking. Though few studies in the literature have addressed this issue, no investigation can be found focusing on identifying modes by physical means. In the current work, sound produced in a cold air-water model was analysed to distinguish various cavity modes. Wave analysis showed that amplitude of sound increased as the mode changed from one to other. From spectrum analysis, it was found that between a certain range of frequencies, there was considerable difference in the sound level as the mode changed from splashing to penetrating. The presence of a second layer over the bath surface did not affect the general outcomes of the analysis. Present work indicates that it may be possible to identify cavity modes by analysing the sound produced from the bath. This would allow greater control of splashing in oxygen steelmaking and potentially help prevent slopping by controlling operation parameters of the process.

Cold Modelling of Splashing Phenomena in Oxygen Steelmaking

In oxygen steelmaking, splashing and droplet formation play a key role in the kinetics of the process. Though splashing has been studied by previous investigators, there is only limited understanding of how different cavity modes affect splashing. Therefore, a cold model study (at various lance heights and gas flow rates) has been carried out focusing on the issue of cavity modes and how it affects splashing phenomenon. Analysis using Fast Fourier Transform (FFT) was carried out on cavity oscillation that showed that frequency and amplitude of oscillation was highest in penetrating mode. Measurements of splashing over a range of conditions showed splashing greatly reduced when cavities went from splashing to penetrating mode. The results were validated and compared with plant data and previous model investigations.