Numerical Simulation Technology Of Casting Solidification Process

Casting Technology, which plays an important role in the national economy,is one of the most widely used material molding method. But,today the traditional casting technology has been the can not keep up with the pace of the development of knowledge-based economy.Computer simulation techniques involved in foundry marks this traditional industry face to modernization. Solidification process,which is an important part of the casting process, has a decisive influence on the whether surface or internal quality of casting. In this paper,based on the analysis of the solidification heat transfer theory, a mathematical model of heat transfer process is established and a program module with independent caculation function is developped, so as to forecast the possible defects of casting in its producing process and optimize the casting process in order to give theoretical directions to optimize the casting process.It is proved that the content researched in this paper has important practical and scientific value.Making quantitative analysis on solidification heat transfer process, Basing on the in-depth study of metal solidification and heat transfer theory,the paper has established a mathematical model in the form of differential equations.Then,through summarying a variety of numerical algorithms on solving differential equations and analysing the factors that has impact on the solidification process, established the differential equations which has definite solution by using finite diference method to make the model discretization in space and time domain. The paper adopted an integrated heat transfer coefficient to solve the heat transfer problem on the boundary of different materials which have different heat transfer coefficient characteristics.Using the temperature recovery mehtod to settle the problem of latent heat realease of the material which has a narrow crystallization temperature range and the equally specific heat method to the material with the wide crystallization temperature range,in order to play to the advantages of both methods and improve accuracy of the calculation.Reaserching on the mode of latent heat realease, changing relationship between Heat release and temperature is determined to be linear mode.Meanwhile,six possible cases are discussioned when using the equally specific heat method to settle the problem of latent heat realease and the caculated results are modified according to the principle of energy balance,so that, the accuracy of the calculation is improved.In the part of program development,with Microsoft VC++6.0 as development platform, object-oriented programming technology is used to develop the calculation module of solidification temperature field independently,and the programming of the mathematical model is implemented. By developing the appropriate interface program, each of the functional modules is dynamically linked to the main program,so, the main program file size is reduced and the running efficiency of the program is improved.By developing the file data reading program, data connectivity between the three-dimensional modeling software and this software come true,then, a set of numerical simulation,including shows of the three-dimensional model,mesh generation,solidification and heat transfer calculation and the simulation results display are implemented. Finally,the interface of the software is simple and easily used,the programming is structured design with good expensibility and readability.In the last,using the sofuware to simulate the heat-transfer process of the parts model,comparing the results with the one of AnyCasting,it shows that the result of our software consistents with the result of AnyCasting,so that the calculation accuracy of the simulation module is validated.