压铸充型过程的SPH方法建模及数值模拟

SPH-Based Modeling and Numerical Simulation of Filling Process of High-Pressure Die Casting

基于欧拉描述的数值方法在求解压铸充型过程自由表面问题时存在一定困难.为提高自由表面数值模拟的准确性,建立了基于纯拉格朗日描述的压铸充型过程光滑粒子流体动力学(SPH)方法计算程序.引入Monaghan边界模型建立了型腔壁面边界条件,通过划分入流区域粒子和流体粒子满足了入流边界条件.采用所编制的程序计算了Schmid验证模型,并将该计算结果分别与实验结果以及采用有限差分方法(FDM)计算的结果进行了对比,发现SPH方法的计算结果更好地表现了充型阶段的自由表面分布,且能更准确地模拟充型形成的空穴的位置和大小.

The numerical method based on Eulerian description is insufficient for solving the free surface flow in the filling process of high-pressure die casting（HPDC）.In order to improve the simulation accuracy of free surfaces,a smoothed particle hydrodynamics（SPH） program with pure Largrangian description is established for the calculation of filling process of HPDC.Then,by introducing the Monaghan boundary model,the solid-wall boundary conditions of mold cavity are determined,and the inlet boundary condition is satisfied by dividing inlet-region particles and flow-region particles.Moreover,the validation model given by Schmid is calculated with the proposed SPH program,and the simulated results are finally compared with both the experimental and the FDM simulation ones.It is found that the SPH results well describe the distribution of free surface in the filling process,and precisely simulate the location and size of the voids formed in the filling process.