基于改进差分网格的高温合金定向凝固数值模拟

Numerical Simulation of Directional Solidification of Superalloys Based on Modified Difference Mesh

辐射传热的准确计算是高温合金定向凝固过程中获得优质铸件的关键因素之一。改进有限差分网格,对高温合金叶片定向凝固传热过程进行数值模拟,并采用不同的工艺参数进行对比分析。结果表明,差分网格修正方法能在一定程度上提高规则与非规则复合几何模型的外表面辐射传热量数值计算精度;当抽拉速度为6mm/min时,合金的固液界面形态最平稳;随着型壳与合金的对流传热系数增大,叶片合金横截面的中间高温区域逐渐减小,直至横截面温度均匀,且温度场是由外向内逐渐降低。

Accurate calculation of radiation heat transfer is one of the key factors to obtain high quality castings during directional solidification of superalloy.The finite differential mesh was modified to simulate the directional solidification heat transfer process of superalloy blades,and different process parameters were used for comparative analysis.The results show that,the mesh modification method can improve the accuracy of numerical calculation of radiative heat transfer on the outer surface of regular and irregular composite geometric models to a certain extent.When the drawing speed is 6 mm/min,the solid-liquid interface morphology of alloys presents the most stable.As the convective heat transfer coefficient between the shell and the alloy increases,the intermediate high temperature region of the blade alloy cross section is decreased gradually until the cross section temperature is tended to be uniform,and the temperature field is gradually decreased from the outside to the inside.