The combination of theoretical analysis, experiment and computer simulation is proposed to verify the correctness and feasibility of theoretical analysis model and computer simulation technology to guide the manufacturing of large-scale high-quality sand castings, reveal the multi-interface heat transfer mechanism in the process of sand casting, and provide technical support for the production of large-scale high-quality sand castings. The main research contents are arranged as follows:
(1) The development and application status of sand casting simulation technology at home and abroad are briefly summarized. The development process of sand casting technology and the research and development status of material thermophysical parameters are described.
(2) The basic theories and methods used in the numerical simulation technology of sand casting process are introduced, the influencing factors of flow field, temperature field and stress field in sand casting process are analyzed, and the formation mechanism and judgment basis of shrinkage cavity and porosity defects in sand casting are studied.
(3) This paper introduces the method of determining the thermophysical parameters of molding sand, designs the test device, measures the temperature data of temperature measuring points in sand castings and molding sand, and obtains the thermophysical parameters of sodium silicate sand by inverse algorithm.
(4) The interface heat transfer coefficient of sodium silicate sand mold is obtained by using the reverse module in the sand casting software, and the influence of different interface heat transfer coefficient on the simulation results is analyzed.
(5) The three-dimensional model of large hydraulic turbine blade is established, the flow field, temperature field and stress field of hydraulic turbine blade in sand casting process are simulated and analyzed by software, and its gating system is improved to predict the casting defects such as shrinkage cavity and porosity that may occur in the process of sand casting, so as to provide basis for actual production.