Overview of lost foam casting numerical simulation technology

In recent years, with the development of casting numerical simulation technology, there are many achievements in the application research of casting process simulation technology, especially in the traditional sand casting and pressure casting. Compared with ordinary sand mold casting and pressure casting, the application of casting process numerical simulation technology in lost foam casting started late.

In 1964, British researchers led by R.D. buttercarried out experimental research on the filling process of lost foam casting, and studied that the liquid metal was filled forward in the form of diffusion, and the filling speed depended on the pattern decomposition speed and the escape speed of its products.

In 1976, Xu Shida and others used photography to study the influencing factors of lost foam casting filling process, such as pouring position, pattern density, pouring speed and alloy type.

Wang. C. M et al. Analyzed and studied the flow and heat transfer of liquid metal in the filling process of lost foam casting of aluminum castings with three-dimensional arbitrary geometry on the premise that the liquid metal temperature at the filling front, the metal static head and the thickness of the pattern had an impact on the pattern decomposition rate. At the same time, they measured the actual filling process, and compared the analysis results with the actual measurement results.

Y. F. Chen et al. Assumed that the moving speed of the free surface of liquid metal in the process of lost foam casting was limited by the flow of liquid metal in the inner gate, improved the flow calculation model of ordinary sand mold casting, created the calculation model of flow field simulation in the process of lost foam casting filling, and verified the calculation results with a simple horizontal disk.

Wei zunjie studied the calculation method of air gap pressure at the filling front, set the calculated air gap pressure as the boundary condition, and simulated and analyzed the flow field in the filling process of aluminum alloy lost foam casting.

Li Fengjun of Tsinghua University, based on the experimental data of liquid metal flow velocity at the filling front, gave the empirical formula of liquid metal flow velocity at the filling front of lost foam casting through linear regression, and then analyzed the evolution of liquid metal flow front according to the method of artificial neural network, so as to simulate the whole filling situation.

S. M.H. mirbagher et al. Improved SOLA-VOF algorithm considering the characteristics of flow field and temperature field in lost foam casting. The new SOLA-VOF algorithm comprehensively considers the air gap pressure and the pressure of liquid metal in the flow domain, iterates the filled grid and partially filled grid at the same time, and then simulates the whole filling process.

On the basis of theoretical research, researchers and commercial institutions in many countries in the world have developed the simulation software of lost foam casting process. For example, technalysis and flowscience in the United States, magma in Germany and ProCAST in France all show some preliminary simulation results.

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