Computational Fluid Dynamics (CFD) Tools for the Management of Bulk Residual Stress

ABSTRACT: A proposal for a Phase II effort that continues the development of a computational fluid dynamics (CFD) based tool for the prediction of bulk residual stresses, started under the Phase I effort, is presented. The key objective in this proposal is to improve the numerical heat transfer methods explored in Phase I via experimentation, theoretical development, and validation. Small scale boiling experiments are suggested for improving the understanding of sub cooled oil boiling heat transfer. In particular, specific experiments are proposed for improving the understanding of nucleate site density, bubble departure size, transition boiling characteristics and film boiling vapor thickness. The experimental activities will provide an additional foundation that will be used to improve the understanding of the physics of boiling oil and help determine improved sub grid scale heat transfer relationships. Additional data for validating the methods will be collected in a pilot-scale facility on a full-size and representative part. An initial release of the software tool is expected at the end of the project, providing a solid foundation for a commercial CFD-based software product. BENEFIT: The primary benefits of the research outlined in this proposal is the development of an engineering software tool capable of predicting heat transfer on a forged part during the quenching process. Currently, there are no Computer Aided Engineering (CAE) software tools available for reliably approximating heat transfer during an oil quenching process. The proposed simulation tool is expected to improve the quality and reduce the costs of manufactured metal parts. In particular, it is expected that the software will provide the necessary tools for engineers to reduce post-heat treat machining and improve the uniformity of part material properties. The commercial product resulting from the proposed research will be the foundations of a software tool that can be applied to a number of parts manufactured for private and military applications. Parts for the military such as turbine disks, large bulk heads, helicopter gears and large gun barrels are some of the items that would benefit from design work that included the application of the software. The automotive industry utilizes large quantities of heat treated parts. Since the corporate culture in this industry is to design in part quality rather than inspecting for the desired part quality it could also benefit from the proposed design tool.