Journal Articles

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Open Access
Tensile mechanical properties and surface chemical sensitivity of technical fibres from date palm fruit branches (Phoenix dactylifera L.)
(Université de M'sila, 2015) Amroune, Salah
The paper describes the manufacturing process and the characterization of the tensile mechanical properties of treated and untreated palm dates long technical fibres. The fibres extracted from Fruit Bunch Branch of Palm Date (FBBPD) have been subjected to alkaline treatment with different NaOH concentrations at room temperature. The experimental results show that the chemical technical fibre treatments provide an increase of the mechanical properties (tensile strength and Young’s modulus) under quasistatic tensile loading. A specific treatment leads a threefold increase of the failure stress. An analysis of stress at failure has been performed over a population of 630 samples using Weibull statistics with two and three-parameters, together with a one-way analysis of variance (ANOVA). FBBPD technical fibres show stiffness and strength performance comparable to the ones of agave Americana L fibres, and higher failure at strength than okra fibres.
Open Access
Etude des caractéristiques élastiques d’une argile expansive stabilisée a faible teneur de mélange ciment chaux
(Université Mohamed Boudiaf - M’sila, 2016) aissa, BAKHTI
La présence des sols gonflants dans plusieurs régions d’Algérie a causée des endommagements aux superstructures souvent assez coûteuses. Plusieurs solutions sont proposées comme remèdes, parmi elles : la stabilisation chimique, mécanique ou physique. La stabilisation des argiles expansives est une branche de recherche qui suscite de plus en plus d’intérêt, donc il y a nécessite de définir un procédé de stabilisation efficace et économique. Le travail présenté dans ce mémoire est base sur une étude de laboratoire sur le caractéristiques élastiques d’une argile expansive de la région de Sidi Hadjeres de la wilaya de M’sila stabilisée par l’incorporation de différente teneurs mixtes en chaux vive et en ciment portland. Pour cela, des essais d’identification et des essais mécaniques ont été effectués sur cette argile et les résultats obtenus mettent en évidence une amélioration certaine et nettement meilleure des caractéristiques géotechniques telles que les paramètres de consistance, la portance et l'augmentation de la vitesse des ondes ultrasoniques qui conduisent à l' augmentation d'élasticité.
Open Access
HARDNESS MEASUREMENTS VIA AN ELLIPSOID-SHAPED INDENTER
(Université de M'sila, 2016) Boudilmi, Aissa
In this theoretical study, we have chosen to use a body of an ellipsoidal geometric form as an indenter, where we determined the mathematical expression of the static hardness as function of the depth and the radii of the area of projected imprint. We used the general formula of the static hardness expressed by the ratio of a force applied perpendicular on the indenter to the resulting area of the imprint; also, we have established the real imprint (cap) of an indenter of revolution ellipsoid form. Finally, geometrical and mathematical approaches have been used to derive the formula of the static hardness expression.
Open Access
A Theoretical Study of Indentation with an Oblate Spheroid Shape
(Université de M'sila, 2016-08) Boudilmi, Aissa
In this study, firstly we introduced general mathematical concepts related to the geometrical form of ellipse and ellipsoid. Secondly, the hardness was calculated when we used an indenter having a geometrical shape of an oblate spheroid; the mathematical expressions of static hardness were determined as functions of the applied load, the radius or the depth of the imprint area. The general static hardness formula was expressed considering the projected and the real area imprint of the oblate spheroid indenter. Thirdly mathematical assumptions were introduced in order to simplify the mirohardness and nanohardness formulas when we used the real imprint area. Finally we did a comparative study between the oblate spheroid and the spherical indenters.
Open Access
Numerical study three-dimensional of mixed convection in a cavity: Influence of Reynolds and Grashof numbers
(Université de M'sila, 2018) Razik, Benderradji
In this work, we present a numerical study of mixed convection heat exchange in a cubic cavity of a laminar three-dimensional (3D) incompressible flow. This study predicted the behavior of the flow structure between Multi clear structure dominated by natural convection when the Reynolds number is small, and a Multi clear structure dominated by forced convection when the Reynolds number is high. First, we fix the Grashof number for the variable Reynolds number. Second, we vary the number of Grashof for which the Reynolds number is kept fixed. The results obtained give a clear comparison with those found in the literature it examines and explains the thermal and dynamic characteristics of the flow.
Open Access
Optimization of the SO3 content of an Algerian Portland cement: Study on the effect of various amounts of gypsum on cement properties.
(Université de M'sila, 2018) Siline, Mohammed; Omary, Safiullah
Portland cement CEM I is obtained from (95–97%) of clinker and (3–5%) of gypsum, according to EN 197-1 (2011) standard. Sulfur trioxide SO3 is the main component of gypsum (Calcium Sulfate Dihydrate CaSO4_2H2O), it may also originate from clinker, the previous standard has limited its content in cement at 4%. It is known that the gypsum acts as a cement setting regulator, however, an appropriate gypsum quantity (optimum) may improve other properties such as: mechanical response, dimensional variations and hydration process. This optimum gypsum content is related to several parameters, namely: SO3 %, cement SSB (specific surface Blaine), C3A % and alkali %. The aim of this work is to find, through an experimental protocol, the optimum gypsum content of an Algerian Portland cement CEM I. 10 variants containing various % of gypsum were formulated, where properties of anhydrous cements, cement pastes and normalized cement mortars were studied. Results show that when gypsum is added below or above the optimum, water demand for normal consistency, setting times, compressive strength, heat of hydration, swelling, drying shrinkage and hydration degree were adversely affected. It has been experimentally demonstrated that this optimum gypsum content is 5.5% by weight.
Open Access
Experimental investigation of bearing wear of a gear unit DMGH 25.4 of horizontal cement mill
(Université de M'sila, 2018-01-15) Menasri, Noureddine; Bouchoucha, Ali
Purpose – Rotating machines play a strategic role in the process; it is the case of a gear unit of a cement mill. These machines are composed of tribo-pairs (bearings and gears, etc.) subjected to mechanical stress and harsh industrial environments. This study aims to make an experimental investigation of bearing wear of a gear unit DMGH 25.4 of a horizontal cement mill. Design/methodology/approach – Several tests were carried out in collaboration with industrial Algerian companies namely spectroscopy, micro hardness, X-Ray diffraction analysis and microscopic examined to wear characterized QJ1244 N2MA bearing. Findings – Experimental results reveal that there are two types of bearing wear: the first is a continuous mode of damage. The second mode is the wear by a third body (wear debris in suspension in oil). The spalling results from the propagation of cracks through the thickness of the material generally give rise to cracks in the sub-layer depth hertz. An unusual hardening observed suggests that the damage was caused by the dissipation of a large surge of frictional energy lasting several milliseconds. It is found also that heating due to insufficient lubrication of the bearing led to the formation of high-density fine carbides in the microstructure of 100Cr6, which tends to decelerate the movement of dislocations during plastic deformation. Practical implications – This study allowed the characterization of bearings wear in industrial mechanical systems. Originality/value – Characterization of the bearings showed that the unusual hardening observed suggests that the damage was caused by the dissipation of a large surge of frictional energy lasting several milliseconds. The microhardness of the worn bearing is very high compared to the beginning wear bearing, which is due to the quantity of carbides formed. The thermo-mechanical stresses do not affect the main phases such as martensite, but they accelerate the fracture propagation at the surface.
Open Access
High-Gradient Magnetic Separation Method for Weakly Magnetic Particles: an Industrial Application
(Université de M'sila, 2019) Chouki, Farsi
The high-gradient magnetic separation process is a technique used in heavy industries, particularly steel mills, to extract magnetic particles from mix-tures. The difficulty of separating the slightly magnetic particles from the nonmagnetic ones lies in the distribution of the magnetic field and the fine-ness of their class to be separated. A use of different separation matrix pro-file is implemented, making it possible to act on the value of the gradient of the inhomogeneous magnetic field. Different matrixes are tested and the re-sults obtained experimentally allows to choose the most efficient matrix form in the operation of extraction which increased by 11% in magnetic fraction yield, 15% iron content and 17% of extraction degree relative to the John’s matrix. This matrix used is consistent with that cited in literatures. The sep-aration technology used can extend its useful application to small particles from very weakly magnetic materials. Its exploitation will result in the method of reducing the degree of pollution and improvement the process of extraction of minerals that has an impact on the environment and on human
Open Access
High-Gradient Magnetic Separation Method for Weakly Magnetic Particles: an Industrial Application
(Université de M'sila, 2019) Chouki, Farsi
The high-gradient magnetic separation process is a technique used in heavy industries, particularly steel mills, to extract magnetic particles from mix-tures. The difficulty of separating the slightly magnetic particles from the nonmagnetic ones lies in the distribution of the magnetic field and the fine-ness of their class to be separated. A use of different separation matrix pro-file is implemented, making it possible to act on the value of the gradient of the inhomogeneous magnetic field. Different matrixes are tested and the re-sults obtained experimentally allows to choose the most efficient matrix form in the operation of extraction which increased by 11% in magnetic fraction yield, 15% iron content and 17% of extraction degree relative to the John’s matrix. This matrix used is consistent with that cited in literatures. The sep-aration technology used can extend its useful application to small particles from very weakly magnetic materials. Its exploitation will result in the method of reducing the degree of pollution and improvement the process of extraction of minerals that has an impact on the environment and on human health as a result a high level of extraction.
Open Access
Influence of the heated blocks on the natural convection in 3D cylindrical and divergent annular duct
(Université de M'sila, 2019) BENKHERBACHE, SOUAD
In this paper, a numerical investigation of natural convection in three-dimensional cylindrical and divergent annular duct is studied. In the inner cylinder of thin thickness, are mounted a cylindrical blocks which subjected to a volumetric heat generation. The governing equations of mass, momentum and energy equation for both the fluid and the solid are solved by the finite volume method using the commercially available CFD software fluent .The effect of the number of heated blocks (N = 1, 2, 3 and 5) and the inclination angle of the divergent (φ = 0°, 15°, 23° and 45°) have been studied . The temperature and velocity contours fields, stream lines also the local Nusselt number have been presented here for Ra = 2.105 and N = 3 while temperature and velocity profiles in the span-wise direction of the flow were plotted for Ra = 1.105 (φ = 0°, 15°, 23° and 45°) and (N = 1, 2, 3 and 5) also the local and average Nusselt number for those geometries.
Open Access
Study of The Influence of External Parameters on Thermal Performance of a Solar Water Collector
(Université de M'sila, 2019) Djedid, Taloub
The purpose of this work is to show the effect of external parameters: albedo and wind speed) on a solar collector inclined plane. The method used consists in cutting the collector into fictitious slices (05 meshes) of length Δx in the direction of the flow of the heat transfer fluid and writing the balance sheets of the exchanges which intervene at the levels of the 06 nodes: from the outside of the glass, the inside of the glass, the absorber, in the peddler fluid as well as the inside and the outside of the insulation. It is convenient for this to use the analogies that exist between the transfer of heat and electricity, the results obtained are the temperatures at the nodes.
Open Access
Computational studies of mono-chalcogenides ZnS and ZnSe at highpressures
(Université de M'sila, 2019) Ferahtia, Samia
A pseudopotential study of structural, electronic, elastic and thermodynamic properties of mono-chalcogenides ZnS and ZnSe has been reported. Two phases such as zinc-blende and rocksalt are considered here. The computations are essentially based on the density functional theory within the local density approximation. Physical quantities such as elastic constants and phonon dispersions have been presented. The lattice constants, bulk modulus, entropy and heat capacity and their temperature dependence are analyzed and discussed. Furthermore, the effect of high pressure on the features under investigation of the materials in question is examined.
Open Access
A comparison of mixed convective heat transfer performance of nanofluids cooled heat sink with circular perforated pin fin
(Université de M'sila, 2019-05) Bakhti, Fatima Zohra
This paper presents a numerical study on the mixed convection of nanofluids in heat sinks with perforated circular fins. Four different types of nanofluids are used as cooling fluids, which are TiO2, Al2O3 and Cu dispersed in pure water as the base fluid. The selected volumetric concentration of nanofluids was chosen in the range (2–10)%. The Reynolds number has changed in the range of 100–400 to ensure that flow remains in the laminar regime and to have the Richardson number 1≤Ri≤22. To study the cooling performance of the heat sink, three-dimensional steady Navier Stokes and energy equations were discretized by the finite volume method using the power-law scheme and have been solved iteratively, using the SIMPLE algorithm. The results show that a significant improvement in heat transfer in the heat sink due to the suspension of nanoparticles in the base fluid compared to pure water, the improvement in heat transfer is intensified with increased Reynolds number and decrease in the volume fraction of nanoparticles. We also found that the low values of the average Nusselt number are obtained for the nanofluid TiO2, the average values for Al2O3 and the highest values for Cu. It is important to note that a slight increase in friction factor and pumping power has been reported when nanofluid is used in the system.
Open Access
Configuration of wind farm in Kaberten region: wind potential and optimal capacity
(Université de M'sila, 2019-10) ZERGANE, Said
The configuration of a wind farm depends mainly on the wind potential and the disposition of the wind turbines in this park. The windiest site is the most favorable for a future installation of wind turbines for the production of electricity, also, in this same site, a too dense arrangement would lead to considerable of power losses under the effect of wake. In this context, it is presented a research work that consists of determining the installation conditions of a wind farm; evaluating the wind farm through measurements of wind speed and the location of wind turbines in the park to minimize the effect of wind turbine interference. In order to do this, an evaluation study of the wind potential for the implementation of a wind farm based on the quantification of the wind in speed and directions firstly proposed. Secondly, a method for optimizing the positioning of wind turbines in a wind power farm is used based on the introduction of the Jensen wake model and the application of the iterative pseudo-random distribution approach of the turbines in the site. Simulation results are presented and discussed using data from the Kaberten site in Algeria and the characteristics of the GAMESA G52 wind turbine.
Open Access
EFFECT OF PRE-POST TIG WELDING HEAT TREATMENT ON CAST NI SUPERALLOY
(Université de M'sila, 2020) C. SAIB; M. ZAOUI; S. Amroune; H. Ghouss
The effect of a preheating (before) and post (after) welding heat treatment on the microstructure and mechanical properties of the scrap blades made of cast INC738LC superalloy is the main goal of the present investigation. The filler used in TIG welding was INC 625 solution hardened superalloyas proposed solution for hot cracking of the cast INC738LC superalloyin literature. The TIG welding was processed with respect to the constant optimized parameters (current, voltage, speed, gas flux rate and number of passes) to make a mechanical properties comparison between as received and the welded superalloy with heat treatedspecimens. The characterization techniques employed in this study are hardness measurements, tensile tests, optical microscopy and scanning electron microscopy. We found that the proposed preheating improves the TIG welding of the INC 738 LC superalloy specimens and the post welding heat treatment as expected enhances its mechanical properties.
Open Access
Characterization and mechanical behaviour of similar and dissimilar parts joined by rotary friction welding
(Université de M'sila, 2020-01) Houria, Benkherbache
This work is a contribution to the study of the rigidity of rotational friction welding of cylindrical specimens made on a parallel lathe. We performed welding of three combinations of parts: steel / steel, aluminium / aluminium and steel / aluminium according to three numbers of rotations of the spindle (900, 1250 and 1800 rpm). To control the rigidity and quality of these assemblies, tensile tests are used followed by ultrasonic testing to ensure that the tips are welded and that there are no internal defects. Hardness profile of the welded zone according to the welding parameters was obtained. Metallographic observations have detected the profile of the various zones welded and affected thermally. The results of the mechanical tests showed that a rotation speed of 1250 rpm can produce a very good weld, with other parameters kept constant.
Open Access
Development and validation of a machining fixture for complex-shaped components based on Plückerian matrix approach and SDT concept
(Université de M'sila, 2020-09) Mustapha, Arslane
In the manufacturing industry, there are several types of parts of complex shapes owning various functions. The turbine blades (buckets and vanes) are one of the most important components in gas turbines. However, these blades have complex shapes and irregular surface curvature which make them difficult to machine. Production of such kind of parts is so complicated and requires a high control of machining process, advanced CNC programming, innovative tools, and special fixtures allowing to maintain exactly and rigidly in a unique position of the part during machining. In order to enhance productivity and reduce operation time, thereby increasing parts quality, the machining fixture has to fulfill several requirements such as allowing a correct location with security and repeatability of the workpiece as well as maintaining conformity and interchangeability of the machined parts. This paper addresses the challenge of machining complex geometry parts by development and realization of a dedicated machining fixture (MF) for holding a mobile blade of a gas turbine. The first novelty of this work is in the application of the Plückerian coordinates method for choosing the locator’s placement of complex-shaped parts. The choice of the locator’s placement during the design process of the fixture is performed based on the maximization of the determinant and minimization of the condition number of the locator matrix (information matrix). The second novelty is in the optimization approach used. The last novelty is in the developed and fabricated machining fixture. The performance of the developed fixture in terms of localization repeatability is evaluated based on the small displacement torsor (SDT) concept. Results show the validity of the developed fixture.
Open Access
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.
Open Access
Nous présentons dans cette thèse une simulation numérique de la convection mixte d’un fluide électriquement conducteur en rotation dans un espace annulaire entre deux cylindres coaxiaux verticaux. La stabilité de l’écoulement est obtenue en appliquant un champ magnétique externe. Cette recherche vise à étudier la zone d’éclatement tourbillonnaire, la marge de stabilité et les couches fluides de l'écoulement en rotation entre deux cylindres coaxiaux verticaux sous l'effet d'un gradient thermique et d'un champ magnétique axial. Les équations gouvernantes de Navier Stokes, de température et de potentiel électrique sont résolues à l'aide de la méthode des volumes finis. Cette étude est divisée en deux parties : la première partie présente un fluide visqueux conducteur (l'alliage plomb-lithium (PbLi)) caractérisé par un petit nombre de Prandtl (Pr=0.032) et placé dans l'espace entre deux cylindres coaxiaux. La combinaison du rapport d'aspect, γ=1.5 et du nombre de Reynolds, Re=1500 pour trois espaces annulaires (R=0.7,0.8 et 0.9) est comparée en termes de stabilité d'écoulement et de taux de transfert de chaleur. Sans champ magnétique, la décomposition du vortex se produit près du cylindre intérieur en raison de l'action croissante de pompage d'Ekman. Les structures en couches fluides sont développées par la compétition entre la flottabilité et les forces visqueuses. L'augmentation de l'amplitude du champ magnétique ralentit l'apparition de l'instabilité oscillatoire et provoque la disparition de l’éclatement tourbillonnaire (vortex breakdown) et réduit le nombre de couches fluides. Les limites dans lesquelles le vortex breakdown se manifeste et la limite de transition entre multiples couches de fluide et une seule couche de fluide sont établies. La deuxième partie de cette étude présente une comparaison de trois combinaisons de rapports d'aspect (γ) et de nombres de Reynolds (Re). L'action de pompage établit une circulation secondaire le long du plan méridien de l'espace annulaire. Pour certaines combinaisons, l’éclatement de vortex s'est produit près de la paroi interne. La bifurcation sous forme de plusieurs couches de fluide devient apparente lorsque la différence de température dépasse une valeur critique. Ces couches fluides jouent le rôle d'isolant thermique et limitent les échanges thermiques entre le haut chaud et le bas froid des cylindres coaxiaux. La décomposition du vortex et les couches de fluide pourraient être supprimées par le champ magnétique; l'augmentation du nombre de Hartmann (Ha) freine l'écoulement peut être. Des diagrammes représentant l'effet de l'augmentation du nombre de Richardson (Ri) sur les couches fluides sont établis. Ensuite, des diagrammes de stabilité correspondant à la transition de la zone à plusieurs couches de fluide vers la zone à une seule couche de fluide en fonction du nombre de Prandtl (Pr) sont obtenus
(université msila, 2021) H. Benhacine; B. Mahfoud; M. Salmi
This research aims to investigate the vortex breakdown zone, the stability margin, and the fluid layers of the rotating flow between two vertical coaxial cylinders under the effect of thermal gradient and an axial magnetic field. The governing Navier-Stokes, temperature, and potential equations are solved using the finitevolume method. Three combinations of aspect ratios (γ) and Reynolds numbers (Re) are compared. The pumping action sets up a secondary circulation along the meridional plane of the annular gap. For certain combinations, the vortex breakdown bubble occurred near the inner wall. Bifurcation in form of multiple fluid layers becomes apparent when the temperature difference exceeds a critical value. These fluid layers play the role of thermal insulation and limit the heat transfer between the hot top and cold bottom of the coaxial cylinders. Both the vortex breakdown and fluid layers could be suppressed by the magnetic field; the increasing of Hartmann number (Ha) would reduce the number of fluid layers. Diagrams represent the effect of increasing Richardson number (Ri) on fluid layers are established. Then stability diagrams corresponding to the transition from the multiple fluid layers zone to the one fluid layer zone for increasing Prandtl number (Pr) are obtained.
Open Access
Analytical assessment of Ain Skhouna PV plant performance connected to the grid under a semi-arid climate in Algeria
(université de msila, 2021) Mohamed El hassen Jed; Razika Ihaddadene; Nabila Ihaddadene; Amaury De Souza
Algeria currently has a number of 24 functional photovoltaic power plants on its national territory, which are poorly investigated. This study focuses on the performance analysis of one of these existing solar power plants. It is located in Ain Skhouna, situated in Saida province, and has a capacity of 30 MWp (polycrystalline solar cell technology). This study was carried out according to the standardized norms IEC 61,724 (IEC) using one year (2018) of data. A linear relationship between the monthly module and ambient temperatures was evaluated (R2 = 0.994). The monthly total loss increases linearly with the increase in monthly ambient temperature and solar irradiation (R2 = 0.98). The system efficiency, PV efficiency, and performance ratio are affected by ambient temperature. The average monthly PV, system, inverter efficiencies, and PR were 13.78%, 13.29%, 96.68%, and 85.52, respectively. These results indicate that this PV power plant remains in very good working condition after two years of service. The effect of climate on PV plant performance was investigated in Algeria by comparing two climates: a semi arid and a hyper-arid. The results indicate that the semi-arid climate is more favorable than the desert climate for PV power plants for producing electricity and that ambient temperature is a more essential parameter than solar irradiation.