Numerical Simulation of Inclusion Removal in a Billet Continuous Casting Mold Based on the Partial-cell Technique

Abstract

A mathematical model has been developed to simulate the fluid flow behavior and subsequent inclusion removal rate in a billet continuous casting mold. The model is then used to evaluate the effects of various nozzle designs and operating conditions on the removal of inclusions originally adhere to the continuous casting mold. The ultimate goal is to obtain the optimal design and operating condition to improve the steel cleanliness.The numerical technique employed in this study is the SOLA-SURF technique incorporated with the partial-cell scheme, which can better approximate the geometry of the simulated system. Other than simulating the flow field of molten steel in the continuous casting mold, the pathlines of nonmetallic inclusions, which are affected by the interactions of inclusion particles and molten steel, are also calculated to directly access the effectiveness of inclusion removal.The model is then tested on a circular billet continuous caster, which requires the model to have the capability to treat curved surfaces in the geometry of the simulated system. Various port designs in the submerged nozzle and operating conditions such as casting speed and submerged depth of the nozzle are evaluated with the calculated pathlines of the inclusion particles for their effects on the cleanliness of the steel. Results of this research show that the flow pattern in the mold region is affected by the design of the nozzle and operation of the caster. It also shows that submerged depth of the nozzle has a more profound effect on the efficiency of inclusion removal than the casting speed.