中文摘要：

提出了一种基于表面模型的气体辅助注射成型（GAIM）流动模拟方法．通过手工选择气道引导线与自动计算气道参数相结合的方法来生成气道网格，避免了中面模型所需的二次建模．将气体的穿透行为作为熔体充填区域的边界条件引入，采用与传统塑料注射成型类似的有限元／有限差分法与控制体积法（CV／FEM／FDM）搭配对塑料充填区域进行求解；采用匹配渐近展开法求解气体穿透界面．本方法的模拟计算结果与实验基本符合，与基于三维模型的模拟相比，具有很高的计算效率以及较好的精度和计算稳定性．

英文摘要：

Flow modeling and numerical simulation of gas-assisted injection molding were proposed through surface model. A technology of generating gas channel mesh semi-automatically was put forward, which combines selecting the path of gas channel manually and calculating the parameters of gas nodes automatically to avoid second modeling. By taking the influence of gas penetration on melt flow as boundary conditions of the melt-filling region, a hybrid control-volume/finite element method/finite-difference method （CV/FEM/FDM） similar to conventional injection molding simulation was employed. The gas penetration interface within the gas channel was solved by applying the matching asymptotic expansion method, which educes an analytical model of the gas penetration thickness ratio. The simulation results of the proposed model are in agreement with the experiments. By comparison with the simulation based on 3D model, this model is high in computing efficiency and very good in the accuracy and stability.