Browsing by Author "Amar Berkache"

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    Energy conversion
    (University of Msila, 2025-12-07) Amar Berkache
    In the context of increasing global energy demand and growing environmental concerns, a thorough understanding of energy conversion processes is essential for the development of efficient and sustainable energy systems. This book is designed to provide undergraduate students, particularly those specializing in Energy Engineering, with a solid foundation in the principles of applied thermodynamics relevant to modern energy technologies. The content is organized into four interconnected chapters that progressively address the fundamental aspects of energy systems. The first chapter examines single-phase thermodynamic cycles that underpin the operation of heat engines and gas-based power systems, including classical cycles such as Carnot, Otto, Diesel, Brayton, and Stirling, along with techniques for improving thermal efficiency. The second chapter focuses on two-phase cycles used in steam power generation, covering the Rankine cycle and its extensions, as well as hybrid energy systems, cogeneration, and an introduction to nuclear power systems. The third chapter introduces exergy analysis as an advanced thermodynamic tool for identifying energy losses and system inefficiencies, with practical applications to gas and steam power plants. Through a structured and pedagogical approach, this book aims to equip students with the theoretical knowledge and analytical tools necessary to understand, evaluate, and optimize energy conversion systems in a sustainable engineering context. The fourth and final chapter addresses the thermodynamics of combustion, a topic that underpins many energy systems based on chemical energy conversion. Students are introduced to the behavior of reactive gas mixtures, stoichiometric calculations, flame temperatures, and the principles of ignition, both spontaneous and controlled. The chapter also delves into chemical kinetics, examining reaction mechanisms and factors that influence combustion processes, such as pressure, temperature, and reaction rates. Overall, this coursebook is intended to reinforce the knowledge gained through lectures, tutorials, and practical laboratory sessions. It also serves as a reference guide for academic projects, research endeavors, and more advanced coursework in the field of energy engineering.
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    NUMERICAL INVESTIGATION OF 3D UNSTEADY FLOW AROUND A ROTOR OF VERTICAL AXIS WIND TURBINE DARRIEUS TYPE H
    (Université de M'sila, 2021) Amar Berkache
    This article presents an analysis of the complex and unsteady flow associated with the functioning of the rotor of a vertical axis wind turbine Darrieus - H. In this study, the influence of different numerical aspects on the accuracy of the simulation of the flow around a rotor of three straight blades in rotation is performed, which are the effect of the turbulence modeling, and the effects of the mesh and the time step. The Delayed Detached Eddy Simulation (DDES) approach is used. The aim of this article is to describe and analyze the unsteady flow in 3D predicted numerically taking into account the effects of arms like blade-arms interference, blade-wake interactions around the Darrieus rotor and the effect of tip vortices. Two-dimensional simulations are used in a preliminary numerical configuration. Then, three-dimensional simulations are performed in order to precisely determine the characteristics of the complex aerodynamic flow associated with the operation of the wind turbine rotor. The flow field around the rotor is studied forseveral values of the tip speed ratio, dynamic quantities, such as the torque and the power of the rotor, that are presented and analyzed. From the results obtained, it is clear that the approach of the Detached Detached Eddy Simulation with the SST K-ω model can be considered as a reliable prediction. A comparison of the performance of the results showed that the predicted coefficients of performance are very close to the experimental data from the bibliography.