Coupled CFD and thermomechanical analysis of cooling in a die quenching tool

Abstract: In the vehicle industry today materials are sought that are both light and have a high strength. One manufacturing method that can produce parts with both these properties is a method called die quenching. During die tool development simulations are used to predict the material properties in the final part and there is a continuous strive for improving the simulation tools. The aim of this report is to demonstrate how a CFD (Computational Fluid Dynamics) problem and a conjugate heat transfer problem can be set up in LS-DYNA and to evaluate how well the simulation results agree with experimental results. Simulations of the cooling of the die quenching is a first step towards performing a complete mechanical forming simulation that is coupled with CFD analysis in order to predict the final part’s material properties more accurately. In the thesis two experiments were simulated. To be able to perform such an analysis a conjugate heat transfer analysis is needed, in the thesis a heated cube was studied because it had experimental values for the temperature available. The flow in a quenching tool is also discussed and the pressure drop in the tool is compared with experimental values. Temperatures from the conjugate heat transfer are compared with experimental values and sources of errors are discussed in both simulations. The conclusion of this report is that the CFD solver in LS-DYNA is a promising tool that can be used to determine more accurate material properties of the final parts in a coupled thermomechanical forming simulation.