A Multiphysics and Multiscale Tool to Predict Transient Boundary Conditions in Autoclave.

A multiphysics and multiscale Computational Fluid Dynamics (CFD) and heat transfer approach is proposed to predict the transient spatial-temporal boundary conditions for processing autoclave-cured composite parts.  An existing CFD software with multiphysics capability, including capabilities for modeling fan, heater, cool radiator, H-slot, conjugate heat transfer, and turbulence, will be adapted in Phase I to analyze the characteristic flow and temperature fields inside an autoclave.   Using a fine-scale model,  the local heat transfer and friction coefficients for the complex surface of composite parts will be extracted and then correlated to the characterized flow Reynolds number.  Once these values are established, the model can be transitioned to a coarser scale to determine the time-dependent thermal and mechanical boundary conditions during processing multiple composite parts inside the autoclave.  In Phase I, the extracted transient local boundary conditions will be interfaced to software that models the mechanics and chemistry environments within the composite to demonstrate the capability of predicting composite part quality.  Phase II will enhance and validate the software tool to address the manufacturing of composite parts containing inserts, complex curvatures, and thick laminates exceeding 1.5 inches in thickness.  As the developed multiphysics software tool can model the system's boundaries, it will reduce the number of expensive autoclave runs needed to start production. It can also provide production lead time flexibility since the operator can intelligently position multiple parts within the autoclave and still achieve the correct cure profile for each.  The validated simulation tool can be applied to other enclosed processing of a product using convective heating and external pressure, such as heat treatment of metal, ceramic, and glass products as well as baked goods.