Research On Continuous Casting Secondary Cooling Optimization Method Based On Particle Swarm Algorithm

Secondary cooling control in continuous casting process is the keyfactor for the billet quality. Due to unreasonable secondary cooling waterof the continuous casting billet, some quality problems often appear suchas internal cracks, center loose, center segregation, lozenge deformation.Therefore, to acquire high efficient continuous casting technology andgood casting quality, research on secondary cooling optimization controlhas important practical significance.Firstly, with secondary cooling optimization control in the continuouscasting as the prerequisite, this thesis analyzed the characteristics of thesolidification heat-transfer process and developed2-D solidificationheat-transfer model. The control equation was discretized by introducingcontrol volume method, and the phase change process was dealt by sourceitem method to solve the secondary cooling solidification processtemperature field, which established the foundation for secondary coolingoptimization in continuous casting.Secondly, aiming at the premature convergence and the easiness of getting into the local extremum point, and the secondary coolingoptimization problem is a nonlinear, non-differential and multi-objectiveoptimization problems, this thesis improved particle swarm algorithm,which based on mutation strategy of evolutionary algorithm, through thesimulation shows that this algorithm improves its convergence precisionand convergence rate, and improves the calculation efficiency in themulti-objective optimization problems.Thirdly, based on solidification heat-transfer model, the improved PSOalgorithm was adopted for the secondary cooling optimization problems.The relations between casting speed and cooling water was determined byusing the least square method. Finally the continuous casting secondarycooling parameters and the continuous casting optimal control model wereestablished.Fourthly, this thesis developed a secondary cooling optimizationsystem interface in VisualBasic6.0platform, which effectively andintuitively shows secondary optimization results, such as the change curveof the temperature at the end of each segment in two-cold area, slabsurface temperature, thickness of the solidified shell and secondarycooling water parameters etc.