Research On Numerical Simulation Of Lost Foam Casting Process For The Case In Bamboo Carbon Manufacturing Equipments

Because of the interaction between foam and molten metal, the fluid field,the temperature field and the capability of filling during the lost foam casting process are different from the conventional casting process, and the prevention from the casting defects become more difficult. Making use of numerical simulation technology, the filling and solidification process of lost foam casting can be observed visually, the cause of casting defects can be grasped, the casting technology parameter can be optimized, and the quality of castings can be guaranteed. In this thesis, the interfacial heat transfer coefficient (IHTC) during casting solidification is calculated to improve the simulation accuracy of the casting process. Then the lost foam casting process parameters of the case in bamboo carbon manufacturing equipments are designed and analysed using numerical simulation technology. The research results in this thesis are summarized as following:1) The model of forward and inverse heat conduction problems for cylindrical casting is established. The code for the models is also compiled. The compared results between the analytical and numerical simulation solution confirm that the model and compiled code of heat conduction for one-dimension is stable and accurate. Moreover, the effects of some parameters in the inverse heat conduction model on the stability and accuracy of calculation results are also discussed in this thesis. The parameters include the damping factor μ, future time step R and time step△t in the forward heat conduction calculation.2) The interfacial heat flux and heat transfer coefficient during lost foam casting are successfully obtained by using the inverse heat conduction method based on the measured temperatures. And it was found that the IHTC varies with time during the casting solidification. The values decrease rapidly down to its mimum value with decreasing of castig temperature. When the casting temperature decreases under solidus curve, IHTC is almost invariant and remains a constant. This provides valuable references for setting accurately the boundary condition in numerical simulation process.3) Lost foam casting process for the case in in bamboo carbon manufacturing equipments is simulated based on the accurate boundary condition, IHTC, and ProCAST software. Some new results provide the useful guidance for the further study on lost foam casting technology of case component and numerical simulation technology applied in lost foam casting process.