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作者开发了一个以优化铸造设计和提高铸造收得率为目的的计算机三维模拟系统。该三维模拟系统包括前处理部分和后处理部分。前处理部分在建立三维初始形状后,能自动地将几何图形分成六面体网格单元。后处理部分通过最简的输入,彩色显示出计算结果。为降低计算费用和减少内存,使用了线性插值、显式有限差分法数值解析热平衡方程,直接采用不同的时间步长计算每个单元的温度,进而开发出一种定量预测缩孔缩松的方法。该方法假设一临界固相率来决定液态金属的补缩条件。在固相率低于(或者高于)该临界值的区域则相应地产生缩孔(或缩松)。在固相率高的区域,固相率梯度成为控制补缩驱动力的关键参数。而固相率低的区域,依靠重力作用就能顺利地实现补缩。模拟预测的缩孔缩松分布与铸钢件的试验结果吻合良好。另外,还介绍了一些实际铸件浇冒口优化设计的实例。
The author developed a computer simulation system to optimize casting design and increase casting yield. The three-dimensional simulation system includes a pre-processing part and a post-processing part. The preprocessing part automatically divides the geometry into hexahedral grid elements after the 3D initial shape is established. Post-processing part of the most simple input, color shows the calculation results. In order to reduce the calculation cost and reduce the memory, linear interpolation, explicit finite difference method are used to solve the heat balance equation numerically, and the temperature of each unit is calculated directly by using different time steps, so as to develop a method for quantitatively predicting shrinkage shrinkage . The method assumes a critical solid fraction to determine the liquid metal replenishment conditions. In regions where the solid fraction is below (or above) the critical value, shrinkage (or shrinkage) is produced accordingly. In areas with high solid fraction, the gradient of the solid fraction becomes the key parameter that controls the driving force for replenishment. The low solid-phase area, relying on gravity can be successfully achieved shrinkage. The predicted shrinkage shrinkage distribution is in good agreement with the test results of steel castings. In addition, some examples of actual design optimization of pouring riser are also introduced.