数值模拟和集中参数分析法确定熔模铸造工艺凝固时间的对比分析

分析了用求解基于有限体积的数值计算得出的简单形状的铸型凝固时间和由集中参数模型预测的同一简单形状铸型的凝固时间的关系。液态金属假定浇注于一个初始的过热体中,在大气条件下冷却。铸型壁的热损失同时有对流和辐射。能量方程求解采用固定网焓方法。可以获得糊状区的液体部分与温度成线性的关系。用A356合金为材料得到的数值模拟结果与相关物体模数的集中参数分析法做比较。实际凝固时间与用集中解法求出的凝固时间的比率,与模数值高达约0.0125相关。在模数为零的极限情况下,这一比率接近了2.36的值。

Comparative Analysis of Solidification Time Determined by Numerical Simulation and Lumped Parameter Analysis in Investment Casting Process

This paper analyzes the relationship between the solidification time of the same simple shaped molds obtained by solving with a finite volume-based numerical computation as well as by a lumped parameter model.The liquid metal has been assumed to be poured at an initial superheat,the cooling condition of which is in the atmosphere.Heat loss of mold wall by convection and radiation imultaneously have been taken into account.The energy equation is solved using a fixed-grid enthalpy approach.The liquid fraction of the mushy zone is obtained from a linear relationship with the temperature.The results from the numerical simulation with A356 as the material have been compared with the lumped parameter formulation relating the modulus of the object.The ratio of actual solidification time with the time obtained from the lumped solution is correlated for the modulus value up to about 0.0125.In the limiting case of zero modulus,the ratio approaches a value of 2.36.