Cold Model Investigations of Fluid Flow and Mixing Characteristics by Bottom-blowing in Discontinuous Metallurgical Reactors

Abstract

Cold model investigations were performed in two and three phase systems, including water-, slag- and gas-phase. The following nozzle-arrangements were chosen: single central nozzle, centric row, eccentric row and eccentric triangle. The investigations show an intensive vortex formation in the bath as a result of a coupled variation of parameters like blowing rate and existence of a slag simulation phase. A clear-cut vortex is evident at an undercritical blowing rate. The buoyant free jets do not describe a stable path to the bath surface. Two liquid zones with two mutually distinct directions of circulation are present. In the case of the eccentric arrangements of the nozzles, a vortex occurs in the smaller partial zone; however, this vortex is not always stable. In the larger partial zone, a stable vortex with circular motion occurs. The tests with eccentric arrangements yield the best mixing results as a whole. The flow conditions in the bath at a supercritical volume flow rate effect the phenomenon of sloshing, that is an oscillating motion of the bath. The critical flow rate depends on the arrangement of the nozzles. The inception of sloshing occurs at a relatively low blowing rate with the use of a single central nozzle. Turbulent regions are observed in the bath here. In the case of eccentric nozzle arrangements, sloshing occurs only at higher blowing rates.