Ansys Casting Temperature Field Numerical Simulation Optimization Process And Defect Prediction Comprehensive Analysis

The casting process involves filling the mold cavity with liquid metal. This discussion excludes the process of liquid metal flowing through the cavity and cooling, and does not consider the liquid flow process. It merely simulates the cooling process after the metal liquid has completely filled the cavity. This process encompasses numerous physical processes and phenomena that significantly impact the quality of the casting. In long-term production practice, due to the lack of investigation into this process and the absence of precise data on the entire cooling and solidification process, reliance has been placed on the accumulated experience of designers and on-site experiments, thereby hindering the development of the casting industry. If the casting process can be simulated, it would be of great importance for optimizing casting processes, predicting and controlling casting quality and various defects, as well as improving production efficiency. Numerical simulation of the temperature field during solidification can achieve the following objectives: provide pouring and molding sequence diagrams, visualize the solidification process, predict macro defects such as shrinkage cavities and porosity, provide foundational data for predicting casting stresses and microstructures, analyze and evaluate, and optimize casting processes by controlling solidification conditions, reduce process preparation error rates, shorten trial production cycles, and lower trial production costs. Therefore, simulating the temperature field of the casting model is both necessary and of great significance.

The simulation of the temperature field during the casting process primarily depends on heat conduction issues. This process mainly involves the cooling and solidification of the liquid casting and the continuous rise in temperature of the mold. This process is heat conduction, so the simulation of the temperature field primarily focuses on heat conduction theory. Specific issues require specific treatment. For heat conduction issues, the selection of convective heat transfer coefficients, i.e., boundary conditions, is primarily considered. Boundary conditions are divided into three categories:

First type of boundary condition—temperature boundary condition, where the temperature at the object's interface with the external environment is known. This type of boundary condition is referred to as the Dirichlet problem.

Second type of boundary condition—thermal conductivity boundary condition, where the specific heat flux along the normal direction at the object's boundary is known. This type of boundary condition is referred to as the Newman problem.

Third type of boundary condition—heat exchange boundary condition, where the heat exchange between the object and the external medium at the boundary is known. Let the temperature of the surrounding medium outside the boundary be T, the heat exchange coefficient between the medium and the object be α, and the thermal conductivity of the object be λ. Then, the heat exchange condition at the boundary is:

This type of boundary problem is also known as the Laubing problem. The heated boundaries of high-temperature components mostly belong to the third type of boundary conditions. Therefore, the boundary conditions applied in the numerical simulation of the temperature field during this casting process are of the third type.

The following is a detailed explanation of the simulation process and analysis process, primarily conducted in Ansys.