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在塑料注射成形充填过程即将结束时,塑料熔体逐步压实,可压缩性不可忽略。基于PG(Petrov-Galerkin)原理的PSPG(Pressure-Stabilizing/Petrov-Galerkin)法可抑制动量控制方程求解中速度与压力插值空间不匹配造成的虚假数值振荡,SUPG(Streamline-Upwind/Petrov-Galerkin)/GGLS(Galerkin gradient least-squares)法可实现对具有对流占优和小导热系数的能量场控制方程的稳定数值求解,由此采用PSPG法和SUPG/GGLS法建立了注射成形可压缩熔体充模流动的稳定有限元计算格式,并对充模过程进行了模拟。数值算例表明:充填过程中熔体的可压缩性一般情况下可以忽略,但在填充即将结束时熔体可压缩流动对计算结果影响较大,基于可压缩性模型模拟得到的填充结束时注射压力比较缓慢的上升,流动平衡更加真实。
Plastic injection molding filling process is coming to an end, the gradual compaction of the plastic melt, compressibility can not be ignored. The PSPG (Pressure-Stabilizing / Petrov-Galerkin) method based on the PG (Petrov-Galerkin) principle can suppress the spurious numerical oscillations caused by the mismatch between the velocity and the pressure interpolation space in the momentum control equations. / GGLS (Galerkin gradient least-squares) method can be used to solve the steady numerical solution of governing equations of energy field with convection-dominated and small thermal conductivity. Thus, the PSPG method and the SUPG / GGLS method were used to establish the compressible melt- The steady finite element calculation format of mold flow was simulated and the filling process was simulated. Numerical examples show that the compressibility of the melt during filling is generally negligible, but the compressible flow of the melt at the end of the filling has a greater effect on the calculation. Based on the compressibility model, the injection at the end of filling The pressure rises more slowly and the flow balance is more real.