HEAT TRANSFER AND FLUID FLOW IN CONTINUOUS SLAB CASTER MOULD

Abstract

Continuous casting is one of the important research areas in the iron and steel industry today. The major problems encountered in continuous slab casting are the formation of cracks, Inter mixing of slag powder with the molten metal which leads to inclusion in slab and the breaking out of solidified shell at exit of the mold due to change in conditions. These defects are due to highly turbulence flow of molten metal in the mold and heat transfer in the mold. Thus the control of quality in continuous casting can be achieved by controlling the fluid flow and heat transfer in the mold of continuous slab caster mold. In present work, the fluid flow and heat transfer has been simulated using a three dimensional unsteady state model based on considerations of fluid flow, turbulence, heat transfer and solidification. Geometry of 890x225x900 mm3 volume and structural grid of mesh size 25 is generated with help of GAMBIT software The different boundary conditions are applied in various zones. A well known CFD software (FLUENT) has been used to solve governing equations to predict the fluid flow and heat transfer in the mold. The effect of applying magnetic field in the mold is studied by inducing source terms in governing equations of momentum and energy. The effect of variation of casting speed, SEN port angle and pouring temperature has been analyzed. After applying magnetic field, flow in mold get stabilized and temperature gradient is improved which leads to improvement in quality of final product. It has been find out that the increase in the casting speed can leads to the breakout of solidified shell in the mold which is future prone to the inclusion and cracks in final product. It has been shown that flow pattern can be changed by changing exit port angle of SEN. It is also find out that the thickness of solidified shell is not a strong function of pouring temperature of the steel.