EUROPEAN STEEL TECHNOLOGY AND APPLICATION DAYS 2017 - ESTAD 2017

Numerical flow simulations have constantly evolved in the last decades and nowadays play an important role in the development of modern converters. The flow inside the converter is highly complex and comprises a whole lot of physical phenomena like supersonic flow, chemical reactions, heat transfer and the flow of gas bubbles in the liquid melt. Due to numerical reasons, not all flow processes can be taken into account, but it’s possible to capture major effects, show tendencies and gain valuable knowledge on multi-phase flow processes inside converters. Subsequently the results of these analysis will be used in the design of new converters. Primetals Technologies has committed itself to develop an efficient approach for modelling the flow and mixing inside the bath during the refining process within reasonable time. In an exemplary manner, a 110t converter was examined and evaluated concerning mixing. A generally applicable method for modelling the flow and quantification of the mixing intensity has been built up. It became clear that there are 2 kinds of vortexes generated inside the flow which are of importance for mixing and global flow. On the one hand there are vortexes formed near the bubble columns at the stirring elements and on the other hand much bigger vortexes which strongly influence the global flow in molten steel bath were observed. Furthermore it was shown that the arrangement and type of the bottom purging elements is a crucial design aspect for the mixing intensity. Especially asymmetric alignment of purging elements produces critical regions with very low local flow velocities. In addition Primetals Technologies has used its full numerical simulation competence to investigate the influence of varying process parameter at converter top blowing, like input pressure drop, to optimize the blowing lance equipment.