The Variable Grid Technology Of Shape Casting And Its Application In Fluid Field Numerical Simulation

With the development of advanced manufacturing equipment in the direction of high performance,integration and green,the key castings of equipment are required to be lightweight and integrated,and the castings internal structure is becoming complex,which leads to difficulties in the design of high-performance casting molding processes.Casting numerical simulation technology can optimize the casting production process,shorten the trial production period,and improve the casting production efficiency.However,these high-performance castings have complex geometrical structures and uneven thicknesses.The number of computational grids is huge by traditional uniform meshing.Numerical simulation consumes a lot of storage space and calculation time,which blocks the practical application of numerical simulation technology.This dissertation studies a variable grid technology of shape castings and applies this technique to the numerical simulation of casting filling fluid fields.The main works are listed as follows:Firstly,the grid generation rules of a variable grid technology,the relationship between the variable grids,the data storage method of the grid cells,and the traversal order of the grids are studied.A shape casting variable grid generation system is established,mainly including the establishment of meshing model,grid relationship model and grid data storage structure model,and formulating a variable grid traversal operation method of shape castings based on variable grid technology.Secondly,the SOLA-Level Set model suitable for the fluid field solution and interface tracking in the casting filling process is adopted.The collocated grid technology and momentum interpolation method are studied for numerical discretization,a numerical discretization method of complex mold casting fluid field based on variable grid technology was studied.The finite volume method was used to discretize the fluid field control equation,and third-order Runge-Kutta's with fifth-order WENO scheme was used to discretize the Level Set function.Then,the numerical simulations of fluid field simulation and fluid interface tracking,based on a variable grid technology and uniform mesh gird technology,are performed respectively.The comparison of numerical simulation results not only proves that the variable grid technology is feasible in fluid field simulation and interface tracking simulation,but also proves that the technology can greatly improve computational efficiency.Furthermore,the mold filling simulation of benchmark casting is implemented based on a variable grid technology.The comparison of benchmark casting simulation results and experiment results shows that the variable grid technology can effectively simulate casting filling process.In addition,the simulation results and calculation time of the variable grid technology are compared with InteCast CAE software,which proves that the variable grid technology is reliable and high efficiency in casting filing process.Finally,the variable grid technology is applied to the simulation of three complex castings filling process,the simulation results show that the variable grid technology can effectively reduce computational resources while simulating shape castings filling process.