Research On Solidification Model Coupled With Heat And Fluid Flow For Continuous Casting Process Of Steel On CUDA

The solidification process of continuous casting involves the physical effect between the fluid flow field,heat field,electromagnetic field and etc.The effect of fluid flow field has been simplified as an increased effective thermal conductivity in a lot of earlier studies,but it could not fully describe the flow of molten steel.Meanwhile,the researches based on coupled multi-physics models also faced with some problems such as too long computing time brought by the complex model.Aiming at the above problems,this thesis studies the coupling interactions of heat field and fluid flow fields under the electromagnetic stirring during the solidification process of the continuous casting,and its parallel computing technology on the high-performance computing platform CUDA.It is implemented to solve the heat-fluid flow coupled model on the CUDA platform.The main contents in this thesis are following:Coupling relationship between heat filed and fluid flow field,and electromagnetic fields is studied.The three-dimensional heat-fluid flow coupled model based on momentum,energy and solute conservation equations is establish and the PISO algorithm based on collocated grid for the numerical solution of heat-fluid flow coupled model is adopted.Wherein the magnetic field on the flow field is a one-way coupling,coupling between electromagnetic body force and momentum equation of the source term.Between the heat filed and fluid flow field is a two-way coupling by thermal parameters,thermal buoyancy term and Darcy attenuation associations.And the parallel algorithm acceleration for solving the heat-flow coupled model on CUDA was implemented.The parallel algorithm design of PISO algorithm for coupling model solution on the GPU was studied.Respectively memory variables kernel function of the heat-flow coupled model in CUDA program has been optimized to improve the caculating performance.The result showed that:under the electromagnetic stirring effect,molten steel do the level rotary motion and the fluid velocity increases gradually outward from a center,close to the frozen area velocity gradually decreases.Compared with the heat model,the center temperature of the continuous casting steel calculated by the heat-flow coupled model is low,and the surface temperature is higher.It is showed that the heat is driven by the convection effect form the billet center passed to the slab surface which conformed to the actual law of change and described the flow of molten steel better.The parallel algorithm on CUDA can respectively 2.21 times speedup for solving heat-flow coupled model.The optimization effect is good.