Abstract
Theoretical study was made and its result was compared with hot model experiment in order to understand gas flow, and heat and mass transfer in the converter with a top blowing lance.
The experiment was made in a 200 kg high frequency induction furnace equipped with a oxygen lance. Post combustion ratio, γ, measured by a mass spectrometer increases with increase in lance height and decrease in oxygen flow rate. Transfer efficiency, ηH, of reaction heat of CO and CO2 formation to metal bath decreases with increasing γ.
Two dimensional equations of continuity, conservation for momentum, enthalpy and gas species were solved numerically under the condition that the reaction rate at a fire spot is controlled by diffusion in a gas phase. The ad hoc model was used for the calculation of effective viscosity. The values of γ and ηH computed under the constant heat and mass transfer coefficients agree with the measured ones except for the effect of oxygen gas flow rate on ηH.
The computed profiles of physical quantities indicate as follows : The gradients of temperature and concentrations between the lance tip and the depressed surface of metal bath were steeper than those in the other region. The maximum temperature and CO2 concentration are in the recirculating flow zone located between the lance tip and the depressed surface.
