Three-dimensional Numerical Simulation Of Casting Filling Process Based On Smooth Particle Hydrodynamics

With the rapid development of modern technology,computer simulation technology is more and more used in practical production practice.During the casting process,the numerical simulation method based on grid method is more mature,but when there is a fluid dealing with free surface,moving boundary and strenuous motion,it will inevitably produce serious numerical dissipation,and it is difficult to maintain the fluid interface accurately.The smooth particle hydrodynamic(SPH)method could solve problems better.In this paper,a three-dimensional numerical simulation study of casting filling process is carried out by means of smooth particle hydrodynamic method,which is more convenient to deal with the free surface motion of fluid in casting filling and will be filled at the same time The change of mold temperature is closer to the actual casting filling process.This article uses SPH method to study the numerical simulation of casting filling process in the following aspects:Firstly,the basic theory and idea of the SPH method are expounded.aiming at the boundary problem in the 3d model of the SPH method,the virtual particle method which is not easy to cause the fluid particles to penetrate the boundary is selected.The three-dimensional mathematical model of single-phase flow in casting filling process based on SPH method is established,and the corresponding C program is written.Through the simulation calculation of the classical dam break hydraulic model and comparative analysis with the experimental results.Secondly,the study of gas-liquid two-phase flow in casting process can not be ignored,and a surface tension model based on SPH method is established.An example of natural change of initial square droplets in three-dimensional solution under the action of classical surface tension is used to verify the correctness of the SPH surface tension model and provide reliability basis for practical engineering application.The accuracy of the surface tension model with large density difference is verified by the simulation calculation of bubble floating example.As the fluid particles flow through the solid-wall boundary,the interfacial tension between the fluid and the solid boundary will occur,so the interface normal direction of these particles is modified by introducing the wall adhesion boundary condition treatment method positive,a surface tension model containing a wall adhesion model is established.A typical model of the flume example is used to verify the correctness of the surface tension model SPH the method with wall adhesion.An example of the wetting wall of droplets is simulated,and the wetting conditions at different angles are simulated to verify the feasibility of the new method.Through the bottom-side hydrodynamic model,the ability of SPH method to deal with complex gas-liquid two-phase is further verified,and compared with the experiment,the correctness,feasibility and practicability of the three-dimensional model of casting filling model based on SPH method are finally verified.Finally,the temperature field model of casting process based on SPH method is established,and the accuracy of the temperature field model is verified by the simulation of heat conduction of flat plate parts,and the correctness and practicability of coupling the charging model and the temperature field model are verified by the three-dimensional model of bottom injection casting filling,which can simulate the actual casting filling process more comprehensively.