Predictive modeling and engineering validation of ladle draining in bottom pouring

In bottom pouring, ladle draining directly affects mold filling stability, solidification behavior, and ingot quality. To describe the draining process under the combined effects of a continuously decreasing liquid level and changes in slide-gate opening, a predictive mathematical model was developed. The model incorporates the geometric characteristics of the ladle and the relationship between slide-gate opening and effective flow area. An equivalent discharge coefficient was introduced to account for engineering factors such as friction loss and vortex flow. Validation using plant data showed that the model can reasonably predict the variation in molten steel weight over time and reflect the stagewise draining characteristics caused by opening adjustment. For the two validation samples obtained under otherwise comparable plant conditions, the average actual pouring time was 660 s, whereas the average predicted pouring time was 748 s, with an average relative deviation of 13.3%. The model provides a quantitative basis for ladle draining analysis, pouring control, and process parameter optimization in bottom pouring.