基于分步法的三维注塑充填温度场数值模拟  

3D numerical simulation based on operator splitting method for temperature of plastic injection molding in filling stage

作　　者：刘永志[1] 赵振峰[1] 申长雨[1] 

机构地区：[1]郑州大学橡塑模具国家工程研究中心,河南郑州450002

出　　处：《化工学报》2011年第5期1455-1459,共5页CIESC Journal

基　　金：国家科技支撑计划项目(2006BAF04B11);长江学者和创新团队发展计划项目~~

摘　　要：注塑成型的充填过程是一个对流占优的能量传递过程。在采用经典Galerkin有限元法求解该瞬态温度场时,对于固定的计算网格,如果时间步长选择的不合理,容易造成其稳定性要求得不到满足,从而导致方程的求解失败。鉴于此,本文采用分步法将该能量守恒方程分解为一个对流方程和一个热传导方程,针对这两个方程的不同特点,分别选择不同的时间步长和求解方案独立进行求解,解决了由于对流项而引起的方程求解失稳问题。另外,针对瞬态热传导方程的求解,分析了利用向后差分法离散其瞬态项时,采用协调质量热容矩阵容易产生不合理计算结果的原因,进而用集中质量热容矩阵代替协调质量热容矩阵对该方程进行求解,得到了合理的模拟结果。最后采用具体的数值算例验证了该模拟方案的正确性。In the filling stage of plastic injection molding,the energy equation is dominated by convection.The simulation of temperature with the classical Galerkin finite element method in a fixed element might be unstable and oscillatory if time step is unreasonable.To get the reliable solution,the algorithm must deal with both convection and conduction,which requires highly different time scales.For this reason,the energy equation was solved by an operator-splitting method.First,the convective part of the problem was solved,and then the conduction term and source term were solved.In this way,particularly effective numerical schemes were used.As this approach used sub-time steps for the convection term,which was much smaller than that for the conduction term,the unstable result caused by convection could be solved consequently.In addition,the lumped mass heat capacity matrix was used to deal with the transient item,which reduced non-physical oscillations that the consistent mass heat capacity matrix possibly led to.For the given examples,the simulation results illustrated that the scheme in this paper had better accuracy.

关 键 词：注塑 充填 温度 三维数值模拟 

分 类 号：TQ320.66[化学工程—合成树脂塑料工业]