Three-Dimensional Numerical Simulation of Injection Moulding

NRC publication: Ye

Méthodes d'éléments finis adaptatives pour les écoulements turbulents

La méthode des éléments finis en mécanique des fluides -- Modélisation de la turbulence -- Méthodes adaptatives pour les écoulements visqueux -- Équations différentielles -- Conditions aux frontières -- Les équations modifiées -- Formulation variationnelle -- Les enjeux numériques -- Résolution en variables logarithmiques -- Estimation a posteriori de l'erreur -- Les variables logarithmiques et l'erreur de la solution -- Opérateur de transition -- Couche cisaillée 2-D avec une variation linéaire de la viscosité turbulente -- Couche cisaillée 2-D avec une distribution gaussienne de la viscosité turbulente -- Couche cisaillée avec un rapport de vitesse U2/U1=0.3 -- Marche descendante de Kim -- Écoulement autour d'un profil NACA0012

Nodal velocity derivatives of finite element solutions: The FiND method for incompressible Navier-Stokes equations

Peer reviewed: YesNRC publication: Ye

Development and validation of a stabilized immersed boundary CFD model for freezing and melting with natural convection

Numerous processes in the automotive, additive manufacturing or energy storage industries require an accurate prediction of the solidification (freezing) and melting (thawing) dynamics of substances. The numerical modeling of these phase changes is highly complex because it includes sharp moving interfaces and strong discontinuities in the material properties. This complexity is often exacerbated by the occurrence of natural convection, which induces a strong coupling between the motion of the liquid and the position of the solid–liquid interface. This leads to strongly coupled non-linear thermo-fluid problems which have to be solved in complex geometries. In this work, we introduce two novel stabilized finite element models to predict the phase change with natural convection. The first model uses a more classical viscosity approach to impose stasis in the solid region whereas the second one is based on an immersed boundary formulation to accurately describe the solid–fluid interface. The efficiency of the stabilization is first demonstrated by studying the Stefan problem. The two approaches to impose stasis are then compared using 2D test cases before they are both used to study melting in a rectangular (2D) and prismatic (3D) cavity. Significant differences are observed in the flow profiles and the solid–liquid interface position between the 2D and the 3D simulations

Thermofluid topology optimization for cooling channel design

A framework for topology optimization of cooling channels is proposed, which paves the way towards automated design of additively-manufactured cooling channels, required in applications such as the efficient heat management of die casting molds. Combining a selection of pertinent techniques and methods, the proposed density-based approach is strengthened by systematic verification and validation steps, including the body-fitted meshing of an optimized design. Furthermore, this work features applications to simplified, yet industrially-relevant cases, as well as a detailed discussion of the effects of the hyper-parameters of the optimization problem. These enable the reader to acquire a better understanding of the control and regularization mechanisms, which are necessary for a robust development towards complex scenarios

Thermal comfort models for indoor spaces and vehicles—Current capabilities and future perspectives

International audienceThroughout this paper, we reviewed the most popular thermal comfort models and methods of assessing thermal comfort in buildings and vehicular spaces. Most of them are limited to specific steady state, thermally homogenous environments and only a few of them address human responses to both non-uniform and transient conditions with a detailed thermo-regulation model. Some of them are defined by a series of international standards which stayed unchanged for more than a decade. The article proposes a global approach, starting from the physiological reaction of the body in thermal stress conditions and ending with the model implementation. The physiological bases of thermal comfort are presented, followed by the main thermal comfort models and standards and finishing with the current methods of assessing thermal comfort in practice. Within the last part we will focus mainly on thermal manikin experimental studies, and on CFD (computational fluid dynamics) numerical approach, as in our opinion these methods will be mostly considered for future development in this field of researc

Three-dimensional free surface flow simulation of segregating dense suspensions

Peer reviewed: YesNRC publication: Ye

First and Second Order Sensitivity Equation Methods for Value and Shape Parameters

Peer reviewed: YesNRC publication: Ye

Three-Dimensional Numerical Simulation of Segregation in Powder Injection Molding

Peer reviewed: YesNRC publication: Ye