Using openfoam for simulation of reactive injection molding as a non-isothermal compressible multiphase flow

Reactive injection molding (RIM) is one of the most important processes for large-scale production of discontinuous fiber reinforced composites with thermoset matrices. The process conditions control the final part performance. To achieve the quality standards and the economic demands of automotive industry, it is crucial to thoroughly design the process by reliable process simulation. State of the art simulation software focusses on thermoplastic injection molding and uses the same models for thermoplastic and reactive injection molding. However, thermosets reveal a complex and different flow behavior during form filling, compared to thermoplastic composites. Therefore, the present study uses a new RIM-focused solver, which is based on the Finite Volume Method (FVM) and uses well-known viscosity and curing kinetic models for thermoset materials. Non-isothermal, compressible multiphase flows are simulated with phase-dependent boundary conditions, separating air and polymer, to enable mold filling and predicting the final fiber orientation distribution. The FVM simulations are conducted with the open source CFD toolbox OpenFOAM. The solver is compared to commercial FEM software and experimental pressure measurements at different points during mold filling. The simulation results of the RIM-focused solver agree well with the experiments, revealing the high potential of FVM for simulation of reactive injection molding. The solver is compared to commercial FEM software and experimental pressure measurements at different points during mold filling. The simulation results of the RIM-focused solver agree well with the experiments, revealing the high potential of FVM for simulation of reactive injection molding.