The Effective Thermal Conductivity Method in Continuous Casting of Steel

The main concept of the effective thermal conductivity method is to include the effect of fluid flow in the heat transfer modelling by modifying the thermal conductivity of steel by a coefficient A to enhance the heat transfer in the liquid pool and the mushy zone in continuous casting.In this work, a case study comparison was conducted by calculating the actual flow field, heat transfer and solidification with a CFD model and comparing it with a model using the effect thermal conductivity method with A values ranging from 1 to 18.The objective of the study was to find out if the effective thermal conductivity can be used accurately to describe the effect of fluid flow and if so, which A values correspond to the CFD models results.The results indicate that the effective thermal conductivity method cannot be used reliably with constant A values: the best match in this study between the CFD model and the effective thermal conductivity method was with A value of 1 in the end of the strand and with values 9-18 in the mould area.It was concluded that main sources of inaccuracy in the effective thermal conductivity method were the use of constant A and the model's inability to take into account the increased heat transfer produced by the SEN.The authors suggest setting the coefficient A as a function of strand location in order to fix these inaccuracies in the effective thermal conductivity method for continuous casting of steel.