Publications Internationales
Permanent URI for this collectionhttps://dspace.univ-boumerdes.dz/handle/123456789/13
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Item Study of nanofluids cavitating flow through a venturi using computational fluid dynamics code(Publishing House of the Romanian Academy, 2025) Benghalia I.; Nehaoua N.; Zamoum M.; Ami I.In this work, we conducted a numerical study of cavitating nanofluid flow through a Venturi. The objective is to investigate the influence of nanoparticles in the base fluid on the cavitation phenomenon. The computational fluid dynamics code (CFD) was selected with a cavitation model. The mixture model for multiphase flow and the k-ω SST turbulence model were adopted. Three fluids were chosen: water, Cu/water and TiO2/water with different volume franctions of nanoparticle (0%, 10% 20%, 30%). The simulation was conducted with inlet and outlet pressures set at 700 kPa and atmosphere pressure respectively. The numerical results are compared with the previous experimental and numerical data for flow without nanoparticle. The obtained results found that, the presence of the nanoparticles in the base fluid lead to a slight increase in the static pressure, the position of pressure recovery a significant decrease in fluid velocity and an increase in the vapor fraction formation in the flow. Also, the increase of the nanoparticle volume fractions φ results a decrease in the pressure recovery position, fluid velocity and an increase in the vapor fraction formation. Therefore, the presence of nanoparticles in the base fluid promotes the phenomenon of cavitationItem Study of nanofluids cavitating flow through a venturi using computational fluid dynamics code(2025) Benghalia, Imen; Nehaoua, N.; Zamoum, M.; AMI, I.In this work, we conducted a numerical study of cavitating nanofluid flow through a Venturi. The objective is to investigate the influence of nanoparticles in the base fluid on the cavitation phenomenon. The computational fluid dynamics code (CFD) was selected with a cavitation model. The mixture model for multiphase flow and the k-ω SST turbulence model were adopted. Three fluids were chosen: water, Cu/water and TiO2/water with different volume franctions of nanoparticle (0%, 10% 20%, 30%) . The simulation was conducted with inlet and outlet pressures set at 700 kPa and atmosphere pressure respectively. The numerical results are compared with the previous experimental and numerical data for flow without nanoparticle. The obtained results found that, the presence of the nanoparticles in the base fluid lead to a slight increase in the static pressure, the position of pressure recovery a significant decrease in fluid velocity and an increase in the vapor fraction formation in the flow. Also, the increase of the nanoparticle volume fractions φ results a decrease in the pressure recovery position, fluid velocity and an increase in the vapor fraction formation. Therefore, the presence of nanoparticles in the base fluid promotes the phenomenon of cavitation.Item Comparative analysis on heat transfer, between a steady and oscillating jet in a cavity(Inderscience Publishers, 2024) Iachachene, Farida; Mataoui, AminaThis paper numerically investigates the cooling of a heated rectangular cavity by a cold slot jet. The study aims to examine the effect of the jet location inside the cavity (Lf and Lh) and Reynolds number on heat transfer, using URANS turbulence modelling. Different flow behaviours, including oscillatory and steady flows, are generated depending on the jet location inside the cavity. The study identifies and discusses the optimal jet locations for achieving optimal cavity cooling. The results indicate that the lateral placement of the jet has a negligible effect on heat transfer across all cavity walls. Additionally, oscillatory flow consistently expands the heat exchange zone along all three walls, resulting in a wider effective exchange area compared to steady flow conditions. The study proposes optimised jet positions within the cavity for specific wall cooling requirements. By considering the optimal combination of jet height and impinging distance, the cooling performance can be optimised.Item Split Control Wind Turbine Airfoil noise with CFD and Acoustic Analogies(Isfahan University of Technology, 2024) Khenfous, Soumia; Maizi, Mohamed; Zamoum, MohammedThis research aims to investigate the impact of a split airfoil on noise emissions from a horizontal-axis wind turbine. The objective is to comprehensively understand the airflow patterns around the airfoil to reduce noise emissions. The study rigorously examines a range of angles of attack, from 0° to 25°, for both the original airfoil and the airfoil with a split, using advanced computational aerodynamics coupled with analog acoustic analysis. The methodology involves two-dimensional flow simulations with Delayed Detached Eddy Simulation based on the Spalart-Allmaras model, enabling precise near-field flow calculations around the airfoil. Additionally, far-field noise predictions, employing the Ffowcs Williams and Hawkings analogy based on simulated sources, reveal the efficacy of the split airfoil design. Results indicate that the split airfoil design effectively reduces noise emissions across various angles of attack. These reductions translate into a significant decrease in the Overall Sound Pressure Level, ranging from 14% to 19%, and remarkable Sound Pressure Level reductions between 12% and 60% across diverse frequencies, showcasing substantial noise improvements in various frequency ranges.Item Numerical assessment of the hydrodynamic behavior of a volute centrifugal pump handling emulsion(MDPI, 2022) Achour, Lila; Specklin, Mathieu; Belaidi, Idir; Kouidri, SmaineAlthough emulsion pumping is a subject of growing interest, a detailed analysis of the fluid dynamic phenomena occurring inside these machines is still lacking. Several computational investigations have been conducted to study centrifugal pumps carrying emulsion by analyzing their overall performance, but no studies involved the rheological behavior of such fluids. The purpose of this study is to perform a computational analysis of the performance and flow characteristics of a centrifugal pump with volute handling emulsions and oil–water mixtures at different water cuts modeled as a shear-thinning non-Newtonian fluid. The studied pump consists of a five-bladed backward curved impeller and a volute and has a specific speed of 32 (metric units). The rheological properties of the mixtures studied were measured experimentally under a shear rate ranging from 1 s−1 to 3000 s−1 and were fitted to conventional Cross and Carreau effective viscosity models. Numerical results showed the flow topology in the pump is directly related to the viscosity plateau of the pseudoplastic behavior of emulsions. The viscosity plateau governs pump performance by influencing the loss mechanisms that occur within the pump. The larger the ν∞, the less recirculation loss the fluid experiences, and conversely, the smaller the value of ν0, the less friction loss the fluid experiencesItem Modeling surge pressures during tripping operations in eccentric annuli(Elsevier, 2021) Belimane, Zakarya; Hadjadj, Ahmed; Ferroudji, Hicham; Rahman, Mohammad Azizur; Qureshi, M. FahedThe aim of this paper is to present a new numerical model to study the drilling fluid flow through eccentric annulus during tripping operations and to investigate the effect of the eccentricity on the annular velocity and apparent viscosity profiles. Many published works studied surge and swab phenomenon using simplified numerical models that do not consider the azimuthal variation of the shear stress in the eccentric annuli. In this paper, the developed numerical model takes into consideration this variation. Non-orthogonal, curvilinear coordinates were used to generate a body-fitted elliptic mesh that maps the irregular complicated eccentric annulus into a simple rectangle where flow equations can be discretized using the finite difference method then solved numerically. Besides, a commercial software (ANSYS Fluent 19R3) was used to support the findings of the numerical model. Results of these models were validated against the experimental data from literature where good agreement was observed with an average relative error of 2.6%, 3.8%, and 6.8% for the three Herschel-Bulkley fluids studied in the eccentric case. The profiles of velocity and viscosity were plotted, the contours showed that we cannot use an average velocity or a single value for the apparent viscosity to describe the drilling fluid flowing through an eccentric annulus, but, the whole profile should be used, instead. The developed numerical model was used in a parametric study to investigate the effect of eccentricity on the relationship between surge pressure and the relevant drilling parameters namely tripping velocity, annular geometry, and fluid rheological properties. The results showed that the eccentricity decreases the surge pressure independently of the previous parameters and that the rate of decrease varies from one parameter to another. The outcome of this parametric study was used to construct a surrogate model using Random Forest Regressor. Predictions from the surrogate model fit the numerical data very well with R-squared of 0.99 and 0.97 for training and test data, respectivelyItem The effect of orbital motion and eccentricity of drill pipe on pressure gradient in eccentric annulus flow with Newtonian and non-Newtonian fluids(Inderscience, 2020) Ferroudji, Hicham; Hadjadj, Ahmed; Ntow Ofei, Titus; Rahman, Mohammad AzizurThe correct prediction of the pressure gradient is the fundamental parameter to establish an effective hydraulics program, which enables an optimised drilling process. In the present work, the effect of the orbital motion of the drill pipe on the pressure drop in an eccentric annulus flow with Newtonian and non-Newtonian fluids is studied numerically for both laminar and turbulent regimes using finite volume method (FVM). Furthermore, the effect of eccentricity when the inner pipe makes an orbital motion is evaluated. Different behaviours are observed in laminar and turbulent regimes. In the laminar regime, the simulation results showed that an increase of the orbital motion speed causes a considerable increment of the pressure gradient for the Newtonian fluid. For the power-law, non-Newtonian fluid in the laminar regime, on the contrary, a decrease of the pressure gradient is observed due to the shear-thinning effect. In the turbulent regime the mentioned trends are predicted to be much weaker. As eccentricity increases, the pressure drop of the non-Newtonian fluid decreases with a more pronounced diminish in pressure drop when the drill pipe is in orbital motion for both laminar and turbulent flow regimes.Item Study of Ostwald-de Waele fluid flow in an elliptical annulus using the slot model and the CFD approach(Taylor & Francis, 2020) Ferroudji, Hicham; Hadjadj, A.; Rahman, M.A.; Hassan, I.; Maheshwari, P.; Odan, M.A.Among consequences that can be induced by a non-uniform distribution of the stress and other causes during the drilling process is the elliptical shape of the well and consideration of this effect would improve the accuracy of the drilling fluid hydrodynamics prediction. In the present work, the elliptical shape of the annular space is simplified to apply the slot model taking into account the rotation of the inner cylinder. Moreover, the Slot model results are compared with the experimental data, as well as, with the CFD outcomes where a reasonable concordance is observed, especially for low ratios of the major and minor semi-axis. Also, the CFD results are validated with the experimental data from the flow loop setup. We concluded that the increase of the major and minor semi-axis ratio of the elliptical annulus results in a linear increase of the Ostwald-de Waele frictional pressure loss in the laminar regime for all considered rotation speeds of the inner cylinder. In addition, the increase of the eccentricity from 0 to 0.75 has a positive effect where the frictional pressure loss is decreased by almost 28% for all rotation speeds for the elliptical annulus ((Formula presented.))Item CFD prediction of hydrogen passive autocatalytic recombiner performance under counter-current flow conditions(Elsevier, 2020) Halouane, Y.; Dehbi, A.Passive Autocatalytic Recombiners (PAR) are frequently used today as safety devices to mitigate hydrogen risk in confined spaces. The present study aims to investigate by CFD tools the PAR performance under potentially adverse counter-current flow conditions. Experimental data obtained from the THAI+ two-compartment facility are used to validate the numerical simulation. Counter-current flow is created by a fan in the larger vessel which produces a downward flow in the second vessel housing the PAR unit. In the simulation, the H2 reaction rate is computed by a correlation given by the PAR manufacturer, and hence no detailed chemistry is necessary. In agreement with test data, the simulation results show that PAR operation is not hindered by the imposed counter-current flow, although the plume exiting the PAR is somewhat compressed compared to that existing in quiescent atmospheres. It is also found that the computed parameters of interest (reaction rates, mean flow velocities, hydrogen PAR inlet/outlet concentration, temperature, pressure) agree well with the measured data. This confirms the usefulness of using CFD simulations to predict PAR behavior in complex flows and geometriesItem Flow simulation and performance analysis of a drilling turbine(the Academic Publication Council of Kuwait University, 2020) Sahnoune, Khaled; Benbrik, Abderahmane; Mansour, Ahmed Saeed Mohamed; Rekik, OussamaTurbodrills are axial hydraulic turbines which are used in drilling hydrocarbons in extreme conditions, possessing advantages over other drilling techniques with their high speed of rotation, and higher operating torques. In The present work, a numerical simulation of a Newtonian Drilling Mud flow was carried out through one stage of this turbine that has a stator and a rotor. The steady state mixing plane model was used for the simulations to take the rotation of the rotor into account besides the spatially averaged property fluxes of the flow. The turbulence K-ε model was used to consider the turbulence effects. Key performance parameters are calculated as a function of rotation speed and they are validated against the experimental data of the same model geometry in real operating conditions, a good agreement have been found between manufacturer power and torque data, and our simulation results for the same variables. Various flow fields are presented such as velocity and pressure, which had a great influence on the performance of the studied turbine. This will lead to choose the best parameters configuration of an optimal field operation.