JAVIER GONZALES MANTECON
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Artigo IPEN-doc 26685 Simplified CFD model of coolant channels typical of a plate-type fuel element2019 - MANTECON, J.G.; NETO, M.M.The use of parallel plate-type fuel assemblies is common in nuclear research reactors. One of the main problems of this fuel element configuration is the hydraulic instability of the plates caused by the high flow velocities. The current work is focused on the hydrodynamic characterization of coolant channels typical of a flat-plate fuel element, using a numeri-cal model developed with the commercial code ANSYS CFX. Numerical results are compared to accurate analytical solutions, considering two turbulence models and three different fluid meshes. For this study, the results demonstrated that the most suitable turbulence model is the k- model. The discretization error is estimated using the Grid Conver-gence Index method. Despite its simplicity, this model generates precise flow predictions.Artigo IPEN-doc 24753 Numerical methodology for fluid-structure interaction analysis of nuclear fuel plates under axial flow conditions2018 - MANTECON, JAVIER G.; MATTAR NETO, MIGUELShell-type fuel elements are widely used in nuclear research reactors. The nuclear fuel is contained in parallel shells, flat or curved, that are separated by narrow channels through which the fluid flows to remove the heat generated by fission reactions. A major problem of this fuel assembly design is the hydraulic instability of the shells caused by the high flow velocities. The objective of the study presented here is the development of a fluid-structure interaction methodology to investigate numerically the onset of hydroelastic instability of flat-shell-type fuel elements, also known as plate-type fuel assemblies, under axial flow conditions. The system analyzed consists of two nuclear fuel plates bounded by three-equal coolant channels. It is developed using the commercial codes ANSYS CFX for modeling the fluid flow and ANSYS Mechanical to model the plates. The fluid-structure interaction methodology predicts a behavior consistent with other theoretical and experimental works. Particularly, the maximum deflection of the plates is detected at the leading edge and it is a linear function of the square of the fluid velocity up to the Miller’s theoretical value. For velocities above this value, a nonlinear relationship is observed. This relationship indicates that structural changes are taking place in the plates. Furthermore, for fluid velocities greater than the Miller’s velocity, an extra deflection peak is observed near the trailing edge of the plates. Thus, structural alterations also happen along the length of the flat-shells.Artigo IPEN-doc 24031 Simplified CFD model of coolant channels typical of a plate-type fuel element: an exhaustive verification of the simulations2017 - MANTECON, JAVIER G.; MATTAR NETO, MIGUELThe use of parallel plate-type fuel assemblies is common in nuclear research reactors. One of the main problems of this fuel element configuration is the hydraulic instability of the plates caused by the high flow velocities. The current work is focused on the hydrodynamic characterization of coolant channels typical of a flat-plate fuel element, using a numerical model developed with the commercial code ANSYS CFX. Numerical results are compared to accurate analytical solutions, considering two turbulence models and three different fluid meshes. For this study, the results demonstrated that the most suitable turbulence model is the k- model. The discretization error is estimated using the Grid Convergence Index method. Despite its simplicity, this model generates precise flow predictions.