凝固过程数值模拟隐式算法时间步长优化模型研究  

Study on Time Step Optimization Model for Solidification Simulation with Component Wise Splitting Method

作　　者：董怀宇[1] 熊守美[1] 程万里[1] 

机构地区：[1]清华大学机械工程系,北京100084

出　　处：《铸造》2004年第9期724-726,共3页Foundry

基　　金：国家重点基础研究规划项目(G2000067208 3)

摘　　要：在铸造过程计算机模拟中,温度场计算采用显式方法由于稳定性的要求,时间步长受限,计算效率低。采用分数步长法-隐式计算,由于其求解方法绝对稳定,因而对时间步长无限制。为了在保证计算精确度的情况下尽可能地提高计算效率,需要动态调节计算温度场的时间步长。本文中以凝固过程温度场的计算时间步长研究为题,提出了单元跨越固液相线时间的概念,建立了自动优化计算时间步长的模型。对实际的不同大小,不同形状复杂程度的铸件进行模拟计算,对均匀时间步长和自动调节时间步长的计算结果进行比较,验证了自动调节时间步长的合理性。In order to improve the computing efficiency of solidification simulation of casting processes, the component wise splitting method was applied to calculate temperature field. A concept of time that casting cells across the liquidus and the solidus temperatures was proposed and a model for time step optimization during solidification simulation was established according to the concept. The solidification processes of casting samples were modeled for the verification by both uniform time step method and dynamically optimized time step method. The simulated temperature fields and the predicted shrinkage defects are in agreement in both cases. Comparison of the simulation results showed that the model for time step optimization can properly adjust time step during solidification simulation and greatly improve the computational efficiency.

关 键 词：凝固模拟 分数步长法 时间步长 优化 

分 类 号：TP391.9[自动化与计算机技术—计算机应用技术]