The PI proposes to develop and validate a new theory for reactive nonisothermal flows in fibrous dual-scale porous media. The research plan will begin with and investigation of the conditions under which the directional mats, used in the manufacture of composite materials, behave like a dual-scale porous medium. Then the "sink'' theory, based on the principle of delayed tow impregnation, will be developed further for the reactive flows in dual-scale media. Using the mathematically rigorous phase-averaging technique, a new set of temperature and cure equations are proposed to account for the absorption and retention of resin by the tows through additional sink terms. The crucial conductivity and dispersivity tensors in these convection-diffusion equations will be measured for steady-state saturated flows in dual-scale media through 1-D flow experiments involving the temperature and concentration of reactants. Later these tensors will be extrapolated to the unsaturated flows through flow simulations in the unit-cells of the dual-scale fiber mats to estimate fluctuations in the velocity and temperature fields. Then a 1-D mold-filling validation experiment involving a reactive resin will be carried out where the measured temperatures in the unsaturated flow regime will be compared with the prediction of the new equation-set. The equations for both the gap and tow regions will be solved simultaneously using the finite element/control volume scheme in an iterative manner. Implication of research: Apart from disseminating research findings through journal and conference publications, the PI will be collaborating with Moldflow, a leading American mold-filling simulation company, to upgrade the physics of their code. The research will lead to the development of research infrastructure through facility enhancement at the PI's lab and training of graduate and undergraduate students in the area of composites processing. Later the PI plans to couple the unsaturated flow phenomena with the formation and migration of bubbles, a leading cause of property-degrading voids in composites, and thus create a unified theory capable of predicting both bubble migration and flow variables. The unsaturated flow theory developed for LCMs in polymer composites will also be used for developing similar physics for LCMs in metal-matrix and ceramic-matrix composites. Education: The PI proposes to develop a multi-pronged strategy to promote education in plastics and polymer composites. First, he plans to develop recently introduced courses in this area under his Career Development Plan such as a lab-based elective, "Processing of Plastics", and two graduate courses, "Flow of Materials" (based on polymer rheology) and "Transport in Porous Media" (with emphasis in composites manufacturing). The PI will also promote undergraduate participation in plastics research through exciting new experiments in the high-tech areas of polymer composites research.
