Investigation on Coherent Jet Potential Core Length in an Electric Arc Furnace

During the electric arc furnace (EAF) refining stage, coherent jets are used to increase the depth of oxygen jet penetration for better oxygen efficiency and stirring of the liquid steel. A coherent jet is defined when the supersonic jet is shrouded by a flame envelope, which leads to a higher potential core length (the length up to which the axial jet velocity equals the exit velocity at the nozzle). In this paper, a coherent jet computational fluid dynamics (CFD) model is developed with detailed consideration of compressible flow properties and combustion effects. The model is validated by comparing the coherent jet axial velocity profile with experimental measurements. Simulation results show that the combustion reaction mechanism used has a significant effect on prediction of flame temperature, which will affect potential core length. The current model uses a 28-step reaction mechanism to achieve both computational efficiency and model accuracy. Turbulence model modification is necessary for accurately predicting the flow properties. The current proposed modifications are needed for accurate prediction of both compressibility and temperature gradient effects.