Browsing by Author "Hamrani, Abderrachid"

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Apports d'approches sans maillage pour la simulation des phénomènes de séparation de la matière: application aux procédés de mise en forme
(2016) Hamrani, Abderrachid; Belaidi, Idir (Directeur de thèse)
Avec l'avancé des méthodes numériques, de nouvelles méthodes dites " sans maillage " sont apparues pour remédier à certaines limitations de la méthode des éléments finis. Ces méthodes ont la particularité de n'employer aucun maillage prédéfini : elles utilisent un ensemble de nœuds dispersés dans le domaine considéré et sur ses frontières. L'objectif de cette étude est de montrer l'intérêt de l'application des méthodes sans maillage basées sur les fonctions de base radiale pour la simulation des procédés de mise en forme en général et de poinçonnage rapide en particulier. Une attention particulière sera portée sur la méthode RPIM qui offre l'avantage de proposer une interpolation nodale. La démarche proposée dans ce document consiste: à rappeler succinctement les principes essentiels des méthodes sans maillage en précisant leurs avantages par rapport aux méthodes classiques, à présenter et à mettre en œuvre la technique numérique de la méthode sans maillage RPIM avec un calibrage des paramètres caractéristiques, et enfin, à traiter des exemples numériques de procédés de mise en forme avec amorçage et propagation de fissure qui confirmeront ces avantages
Coupling of inverse method and cuckoo search algorithm for multiobjective optimization design of an axial flow pump
(SAGE Publications, 2019) Chikh, Mohamed Abdessamed Ait; Belaidi, Idir; Khelladi, Sofiane; Hamrani, Abderrachid; Bakir, Farid
This work describes the application of a multiobjective cuckoo search method for turbomachinery design optimization of an axial pump. Maximization of the total efficiency and minimization of the required net positive suction head of the pump are the two objective functions considered for the optimization problem. The optimization process is carried out on a range of imposed volumetric flow rates, with taking into account at each discretized radius between the hub and tip of the rotor: the profile camber, rotor wall thickness, angular deviation, and the solidity, regarded as geometrical constraints and nominal flow rate as mechanical constraint. Two strategies are proposed in order to solve the problem. In the first one, three forms of mono-objective model with two variables, total efficiency and net positive suction head, are considered. In the second one, a multiobjective model with nondominated sorting scheme is adopted. A comparative evaluation of results obtained from the proposed approach with those of a reference machine and genetic algorithm allowed us to validate the present work
An efficient reduced-order method with PGD for solving journal bearing hydrodynamic lubrication problems
(Elsevier, 2016) Cherabi, Bilal; Hamrani, Abderrachid; Belaidi, Idir; Khelladi, Sofiane; Bakir, Farid
Numerical analysis of steady-state performances of hydrodynamic misaligned journal bearings considering surface texturing effects
(2018) Manser, Belkacem; Belaidi, Idir; Khelladi, Sofiane; Hamrani, Abderrachid
Misalignment affects nearly all the bearing performance characteristics including the minimum film thickness, pressure field, friction torque, leakage flow rate, and moments. This study presents investigations related to the combined influences of shaft misalignment and texture location on the hydrodynamic journal bearing performances. A numerical study is used in the analysis of spherical texture shape effects on misaligned bearing characteristics. The Reynolds equation of thin viscous films is solved using finite difference technique by taking into account Reynolds boundary conditions. The numerical results show that the performances of misaligned journal bearings can be improved through an appropriate arrangement of the textured location on the contact surface
A numerical investigation of the flow pattern between finite–length conical cylinders
(2017) Merah, Abdelkrim; Mokhtari, Faiza; Kelaiaia, Ridha; Hamrani, Abderrachid; Lalaoua, Adel
Performance of hydrodynamic journal bearing under the combined influence of textured surface and journal misalignment : a numerical survey
(Elsevier, 2019) Manser, Belkacem; Belaidi, Idir; Hamrani, Abderrachid; Khelladi, Sofiane; Bakir, Farid
A predictive model of the optimal tool edge geometry for veneer cutting processes
(Taylor et francis, 2019) Bouarab, Fatma Zohra; Aknouche, Abdelhamid H.; Hamrani, Abderrachid
Veneer cutting is a specific machining process, where the chip is the final product. The objective of this article is to investigate on the optimal tool edge geometry, using particle swarm optimization (PSO) algorithm, to obtain the desired veneer thickness. The challenge is to maintain the best quality of veneer product with the control of pre-splitting condition and thickness variation. Numerical results obtained from PSO algorithm are compared and verified with the experimental ones. The proposed model allows us to predict the characteristic tool angles for different chip thicknesses and friction coefficients. For chip thickness range greater than 2 mm, the presplitting condition is no longer satisfied, as in the case of rotary peeling veneer, the need of using pressure bar becomes primordial.
Résolution d'un problème de convection naturelle en 2D et 3D par la méthode spectrale
(AFM, Association Française de Mécanique, 2017) Bouarab, Samia; Mokhtari, Faiza; Kaddeche, Slim; Hamrani, Abderrachid; Merah, Abdelkrim; Haddad, Fadila
L'objectif de ce travail consiste à étudier le problème de la convection naturelle à l'intérieur d'une cavité carrée différemment chauffée à l'aide de la méthode spectrale. Les simulations numériques bidimensionnelles et tridimensionnelles sont effectuées pour différents nombres de Prandtl et de Rayleighcaractéristiquesde l'écoulement du fluide à l'intérieur de la cavité connu sous le nom d'écoulement de Hadley. La simulation numérique des écoulements incompressibles par les méthodes classiques tels que les différences finies, volumes finis et éléments finis, nécessite des temps de calcul relativement longs et une capacité de stockage très importante. Un modèle basé sur les méthodes spectrales a été développé et a mis en valeur la précision, la simplicité et la rapidité d'une telle méthode, notamment pour des simulations voulues de plus en plus proches de la réalité des processus multi-physiques complexes. La méthode spectrale sera utilisée dans notre étude afin d'effectuer des modélisations bidimensionnelles et tridimensionnelles des écoulements incompressibles en formulation vorticité-fonction de courant pour le modèle 2D et en utilisant la méthode d'Uzawa pour le modèle 3D. Les résultats de la simulation d'écoulements incompressibles par méthodes spectrales seront comparés à ceux obtenus par différences finies et en termes de temps de calcul et précision des résultats
Texture shape effects on hydrodynamic journal bearing performances using mass-conserving numerical approach
(Taylor & Francis, 2020) Manser, Belkacem; Belaidi, Idir; Hamrani, Abderrachid; KHELLADI, Sofiane
It is a known fact that incorporating textures in the contact surfaces can significantly enhance bearing performances. The purpose of this paper is to outline the effects of texture bottom profiles and contour geometries on the performances of hydrodynamic textured journal bearings. The analysis was conducted using computational approach to test eight texture shapes: rectangular, cylindrical, spherical, triangular (TR, T1, T2, T3) and chevron. The steady-state Reynolds equation for modelling the hydrodynamic behaviour of thin viscous film was solved using finite difference technique and mass conservation algorithm (JFO boundary conditions), taking into account the presence of textures on both full film and cavitation regions. The comparison with the benchmark data shows good consistency and an enhancement in bearing performances (load carrying capacity and friction). The results clearly show that the mechanisms of wedge effect and micro-step bearing for the full/partial texturing feature are the main crucial parameters, where the convergent wedge effect present in T2 triangular texture shape can significantly enhance the load-carrying capacity, while the divergent wedge action causes a net load loss. Considering the right arrangement of textures on the contact surface, their surface contours can have a significant impact on the performance of hydrodynamic journal bearings at high eccentricity ratios
Thermal analysis of steady-state performances of hydrodynamic misaligned journal bearings considering surface texturing effects
(2018) Manser, Belkacem; Belaidi, Idir; Khelladi, Sofiane; Hamrani, Abderrachid
Bearing misalignment can affects nearly all operating performances: minimum film thickness, pressure distribution, thermal field, friction torque, leakage flow rate, and cavitation. In this study, we present a computational investigation related to the combined influence of surface texturing and journal misalignment on the performances of hydrodynamic journal bearing. To this end, a numerical analysis is performed to analyze the effect of a spherical texture shape on misaligned bearing characteristics. The model employed herein is solved using a finite differences scheme with mass conservation algorithm (JFO boundary conditions) and oil mixing temperature concept. Preliminary results are consistent with the reference ones, and show that the performances of a misaligned journal bearing can be improved with an appropriate surface texturing topography