Numerical Simulation Method Of Heat Transfer/Solidification Of Continuous Casting Slab Based On Meshless Method

The complex heat transfer,flow,solidification and mechanical behavior in the mold is the key in quality control of slab continuous casting.The hostile working condition has brought great obstacles for the direct detection of high temperature molten steel and slab shell.The numerical simulation method based on meshing,including the finite difference method and the finite element method,has become the main means to research the solidification behavior of continuous casting slab.With the in-depth research,the limitations of meshing-based numerical simulation methods appeared gradually,for example,it cannot reconstruct the solidified shell shape accurately and trace the liquid-solid mushy zone,and it is difficult to deal with some complex problems such as large deformation and crack propagation.The meshless method is fast developed in recent years,which uses a series of discrete nodes to replace mesh elements and topological structures.Due to getting rid of the mesh restraint,meshless method has remarkable advantages in solving adaptive,crack and large deformation problems.In view of this,this paper tried to develop the simulation model of heat transfer and solidification of continuous casting slab based on Element-Free Galerkin method,and the process of the model derivation,equation discretization,nodes arrangement,software development and result verification were studied,which lay a foundation for the application of meshless method in continuous casting process and the subsequent crack prediction.In this paper,a two-dimensional unsteady transient heat transfer mathematic model of slab solidification in mold based on Element-Free Galerkin method was built,which was according to the moving least square method and variational principle.On this basis,an object-oriented meshless numerical calculation software for slab solidification process by Language C++ was designed and developed.Taking the solidification of billet as an object,the related calculation parameters were determined through calculation.Then,the heat transfer and solidification behavior of billet were simulated by arranging the uniform,increased density and random distributed nodes.The calculation results of the Element-Free Galerkin method are compared with the reference solution and the solution of finite element method.The results show that,Element-Free Galerkin method performs better than the finite element method in terms of accuracy,adaptability and mesh-dependence.Finally,taking the solidification process of wide and thick slab as the research object,the non-uniform heat flux was calculated from the temperatures measured by the thermocouple and was used as the boundary condition to investigate the non-uniform heat transfer and solidification characteristics of the continuous casting billet,and the suitable node arrangement methods for non-uniform solidification calculation were also discussed.The conclusions provide references for further applying the meshless method to the numerical calculation of heat transfer,solidification and stress/strain behaviors in continuous casting process.