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1、河北工业大学硕士学位论文 i 铸件铸件充型过程充型过程三维三维数值模拟数值模拟技术技术研究研究 摘摘 要要 铸件充型凝固过程数值模拟是当前材料加工领域的研究热点，铸造过程流场和温度场 及其耦合的数值模拟在铸造仿真系统中占有重要地位。同时流场是计算量最大，耗时最多 的一个过程，也是影响数值模拟实用化的重大障碍，因此研究高效率的流场对推进数值模 拟软件整体水平有很大的意义。 论文在原有流场只适用于简单反重力充填模拟的基础上，改进流场计算技术使之适用 于各种铸造充填方式的模拟计算；并继续开发了充型过程流场与温度场耦合模拟计算程 序，以及能以多种方式显示计算结果的后处理程序。 在流场计算方面，在全面比
2、较各种数值计算方法的基础上，采用了在国内外应用较少 的数值计算方法Simple 结合守恒标量法来计算铸件充填流动过程。 Simple 算法可以较 为准确的模拟出充型过程流场的流动状态，用守恒标量法可以准确地捕捉自由表面网格， 不需要确定自由表面取向，易于进行三维计算。通过对实验铸件“反重力充填大平板”和 实际铸件“链轮、锤头、履带板”等的对比计算表明，与当前软件所采用的 Sola-VOF 法 相比较，该方法更为准确。 论文将流场计算所必须的 50 个三维数组全部设为动态数组，并且重新归整了流场计 算的出口及入口条件，使所开发的程序可以计算任意数量网格的铸件三维流场，可以计算 各种条件下的流动过
3、程， 大大提高了计算速度， 使软件的应用范围扩大到适用于所有情况， 将软件水平提高到商品化的高度。 论文将模拟结果与反重力实验对比，计算结果表明模拟情况与实验可以很好的吻合。 还与 Ft-star 和 ProCAST 在准确性和速度方面进行对比，结果表明，和其他软件模拟情况 吻合很好，证实了计算的正确性，但计算速度有待进一步改进。同时对如何提高计算速度 作了理论分析。 所开发的流场与温度场的耦合程序，通过对试件的模拟结果的分析也表明其合理性。 该项工作的完成为后续的高速流场，紊流计算、流场与温度场的耦合及为后续缺陷预测等 工作的开展打下了良好基础，搭建了可扩展性平台。 采用 C+Builder
4、 技术和 OpenGL 技术，架构了软件框架，编制了用户界面和后处理显 示程序。可以满足基本的计算要求和后处理显示要求。 关键词：关键词：铸造，数值模拟，充型过程，耦合 铸件充型过程三维数值模拟技术研究 ii MOLD FILLING PROCESS RESEARCH FOR THREE-DIMENSIONAL NUMERICAL SIMULATION OF CASTING ABSTRACT The numerical simulation for foundry process is now a hot research point in material processing. The f
5、low field simulation and temperature field simulation and the couple simulation of these two fields have taken an important role in numerical simulation of casting process. The flow field is one of the heaviest workload and of time consuming, and is also the most important part for commercialization
6、 of numerical simulation software. So it has great significance for investigating high efficiency method for calculating flow field of casting process in updating the level of whole numerical simulation software. On the base of the original program of flow field which can only calculating the simple
7、 anti-gravity flow field, an improved program has been developed for simulating almost all kinds of mold filling process. Then a program was also built up for coupling calculation of flow field and temperature field, and so do a post processor which is able to display computing result in many kinds
8、of pattern. For calculation of flow field, based on the investigation and analysis of each kind of numerical algorithm, an approach named Simple and Conservative Scalar Method was chosen to build up mold filling codes of our software, and this algorithm was used less in the world so far. The Simple
9、Method can precisely calculate the flowing process during mold filling of casting, in the meantime the Conservative Scalar Method can precisely capture the free surface of fluid flow without determining the orient of the grid occupying free surface of fluid, so it is more easy to do 3-dimentional si
10、mulation for real casting process. The mold filling process of a test castinga plate filling in anti-gravity ways, and several real castingschain wheel, hammer, creeper tread, was calculated by our codes and other commercializing software, and the result showed that the algorithm used in this paper
11、had more precision than Sola Method used in these commercializing softwares. In addition, several new technology are worth to comment, they are: all the static arrays no less than 50 using in our codes had been changed into dynamic arrays successfully; the outlet condition and inlet condition have b
12、een rebuilt successfully; and the type and value of convergence had renewed; and all these breakthrough in simulation technique have greatly promoted our programs running velocity, expended the application range of our software to fit to almost mold flow conditions. In the end, by these new techniqu
13、es, it is possible for commercializing of our software. In the test part of the paper, the simulation result of anti-gravity filling of a big plate was relatively good in accordance with the experimental result. Afterwards, selecting several real 河北工业大学硕士学位论文 iii castings to compare the accuracy and
14、 velocity of the codes with Ft-star and ProCAST software, it has indicated that the program is excellent in precision, however, the velocity still need to be improved. A theoretical analysis was also done in the paper. The reasonability of the coupling calculation program for flow field and temperat
15、ure field was showed by the simulation result of a test casting. And this study has laid the foundation of the subsequent study for high speed and turbulent flow field simulation and other simulation study such as shrinkage porosity prediction, etc. Finally, using C+Builder and OpenGL, a friendly in
16、terface and post program were constructed, which can meet the requirement of calculation and post processor display. KEY WORDS: foundry, numerical simulation, filling process, coupling 原创性声明原创性声明 本人郑重声明：所呈交的学位论文，是本人在导师指导下，进行研究工作所取得的成 果。除文中已经注明引用的内容外，本学位论文的研究成果不包含任何他人创作的、已公 开发表或者没有公开发表的作品的内容。对本论文所涉及的研究工作做出贡献的其他个人 和集体，均已在文中以明确方式标明。本学位论文原创性声明的法律责任由本人承担。 学位论文作者签名： 日期： 关于学位论文版权使用授权的说明关于学位论文版权使用授权的说明 本人完全了解河北工业大学关于收集、保存、使用学位论文的规定。同意
