By virtue of its incomparable chemical, magnetic, electrical, optical and catalytic properties, the alloy of the Ga- Sm system is gaining importance in the high-tech industry. However, the lack of experimental thermodynamic data on this system made it difficult to design efficient extraction processes. In this regard, thermodynamic calculations can serve as a cost effective tool in terms of time and money in order to design a process to explore the thermodynamic properties of this system. Hence its modeling using the CALPHAD method via Thermo-calc. The Orthorhombic, Rhombohedral, Bcc, Hcp and liquid phases found in the solution were optimized with the substitutional solution model by the Redlich-Kister equation. The Ga-Sm binary system contains five stoichiometric compounds: Ga6Sm_BT, Ga6Sm_HT, GaSm, Ga3Sm5and GaSm3 and the Ga2Sm intermetallic compound, which have a wide homogeneity range, were treated as the formula (GA)2,(Ga,SM)1 by a two-sublattice model with Gallium and Samrium or Gallium on the first sublattice, and Gallium and Samarium on the second, respectively. A set of thermodynamic properties and parameters of the Ga-Sm binary system was obtained, and they are in good agreement with the experimental thermodynamic parameters available in the literature.
This paper addresses the problem of natural convection in H-Form cavity with differentially heated side walls having two circular adiabatic obstacles. To achieve accurate solutions of the equations system defining this study, the computational methods are founded on the finite element method (FEM). Numerical illustrations have been carried out and discussed for several Rayleigh numbers from 10 to 106. We show the impact of Rayleigh number as a crucial parameter on both the heat transfer and the fluid flow. We deduce an important finding with H-Form cavity, the Rayleigh number hasn't a strong effect on both the characteristics of the fluid flow and the temperature distribution for the values ranging from 10 to 104, unlike the case of square cavity. However, its effect starts to appear from Ra = 105. The achieved results are discussed and compared with preceding works in the literature to show their effectiveness.
Due to the important function of tire rolling over obstacles, this work aims to analyze all the tire parameters and characteristics based on the tire dynamic. However, those tire dynamic responses and vibration properties are virtually simulated using 20-Sim analysis which has recently been recognized as a significant analyzed tool for tire characteristics inquiry. The objective of this paper is to determine the limited rigid structure of a tire rolling on a road by simulating the Bond Graph proposed model for this tire connected to piezoelectric beams which can produce utile electric energy using the energy loss in the tire by the longitudinal force. The tire model was developed with real geometry and material for dynamic response of the tire rolling over strictness road. The simulation results for the bond graph model of a tire rolling on a road was generated using the random function on MATLAB-Simulink.
Nano fluids are considered to be very important for improving heat transfer and well suited to practical heat transfer processes, this work presents a set of numerical studies of forced convective flow under laminar, transitional and turbulent flow regimes, using nanofluids in different geometries of solar collectors. The addition of nanoparticles of metals, metal oxides, or carbon nanomaterials, to a base fluid improves the thermal performance of energy systems. The study is carried out on numerical studies of forced convection in solar collectors to obtain a detailed summary of the influence of several parameters such as the type of nanoparticles, volume concentration, particle size, shape, thermal and hydrodynamic characteristics of forced convection thermal transfer. Finally, the work provides an overview of the different CFD approaches used in the numerical simulation of nanofluid flows and examines the advantages and disadvantages of each approach.
Geographical Information Systems (GIS) and hydraulic models are decision support tools for intelligent, fast and efficient management of drinking water supply systems, particularly for diagnosing the functioning of water supply networks. In this work the software Arc-GIS was coupled with the hydraulic model EPANET 2.0, and applied to a case study area, Pressure Stage 85 of the Greater Casablanca, located in the West-central part of Morocco, at the edge of the Atlantic Ocean. This pressure stage is in the center of the Greater Casablanca and consists of three pressure sub-stages (85 Non-Modulated stage (85 NM), 85 Modulated stage (85 M) and 85 industrial stage (85 IND)). It has an overall linear form of about 1308 km (about 18% of the total network) with heterogeneity in age and type of pipes. The floor distributes a volume of 170,000 m3 / day, i.e. one third of the total volume distributed to the Greater Casablanca network. It is also characterized by a spatial heterogeneity of habitats (domestic and industrial areas) with a significant variation in topographic scores ranging from 0 to 85 m. The results of this work have shown that a coupling between a GIS and a hydraulic simulation model provides the drinking water system managers with efficient and rapid responses to better understand and analyze network malfunctions. This study permitted the modelling of the network hydraulic behavior during different periods of the day and identified the variation range of velocity in the network, to locate the areas with high pressure (> 5 bar) and the zones sensitive to leak's appearance. The analysis of these results allows us to recommend the installation of five pressure regulating valves at specific locations. The combination of GIS and hydraulic models as a management and performance tool helps the operator in the assessment of the reliability and the state of existing networks, to analyze and study solutions to problems and to plan and test the various scenarios for future management.
Palm waste is generated in the oasis and poorly valued by burning in random way. This waste can be recovered in many methods according to their physicochemical characterization. The organic values of EFB could allow us to use anaerobic digestion (AD). The elementary compositions are used to estimate the heating value for thermochemical conversion (TC). The study aim is to explore the energetic potential (Ep) of EFB using the AD and TC. The Ep results are 10.87 and 39.1 GWh/y, respectively.
This paper deals with thermo-physical behavior of eco-composite based on concrete material reinforced with glass waste as fine aggregates. Two types of fine aggregates were used: natural sand (NS) with Dmax<4.75mm and recycled waste glass (RWG) with Dmax<1.25mm. The effect of the incorporation of three volume of RWG (10%, 20% and 30%) on density and thermal conductivity at dray state of concrete based eco-composite was investigated. The thermal conductivity was measured by FP2C device using a hot wire method. The obtained results showed a reduction in dry weight of concrete cube specimens and a decrease in the measured thermal conductivity by up to 17% with 30% of RWG. These results demonstrated also the possibility of using waste glass instead of sand in structural materials as the thermal capacity of the composite is increased.
A better understanding of the optical, microphysical and radiative properties of aerosols is a critical challenge for climate change studies. In this study, the aerosol optical, microphysical, and radiative properties were investigated over three sites (Oujda, Saada, and Ouarzazate) in Morocco, Northern-Africa. Using ground-based Aerosol Robotic Network (AERONET),the annual mean aerosol optical depth at 440 nm (AOD440) was found high at saada (0.21 ± 0.11) followed by Ouarzazate (0.17 ± 0.11), and low at Oujda (0.17 ± 0.09). The maximum values of AE440–870, FMF500 coincide with a peak of activity production of dust from each region. The evolution of single scattering albedo is almost similar for every sites and indicates a very important trend in the diffusion. The averaged aerosol direct radiative forcing (ARF) retrieved from the AERONET showed a strong cooling effect at the bottom of the atmosphere (BOA) and significant warming within the atmosphere (ATM), representing the important role of aerosols played in this sites of Morocco. However, the ARF in Oujda and Ouarzazate seem identical despite the great weather disparity between the two sites.
The latent heat thermal energy storage (LHTES) systems, that uses phase change materials (PCMs), has taken attention of researchers because of their higher energy density and almost isothermal storage. However, the low thermal conductivity of most PCMs makes it necessary to develop effective techniques to improve the heat transfer. To overcome this disadvantage, several techniques have been proposed to improve the heat transfer of LHTES. In this sense, the performance of the proposed system, duplex concentric tube with annular fins, is investigated using a 2D axisymmetric model with Comsol Multiphysics software, considering charging and discharging processes. The main objective of this work is to provide the optimal heat transfer fluid (HTF) injection scenario of the studied system for charging and discharging processes. As a results, the top HTF injection scenario can reduce the melting and solidification time by 10.66% and 15% respectively compared to the bottom HTF injection one. Therefore, the top HTF injection scenario is more performed and recommended.
Two-dimensional steady laminar natural convection of a viscoelastic fluid represented by generalized second-grade fluid model in a square enclosure is studied. The cavity is submitted at its vertical sides to a uniform density of heat flux while the horizontal walls are insulated, without slipping conditions at all the solid boundaries. The governing conservation and constitutive equations with the corresponding boundary conditions are solved by finite volume method in a collocated grid system. The contributions of shear rate dependent and elastic characteristics of the viscoelastic fluid are investigated on momentum and heat transport. The effects of elastic number (E) in the range 0 - 1 on heat transfer and fluid motion are interpreted for a power-law index (n) in the range 1.4 - 0.6 and nominal values of Rayleigh number (Ra) range of 10(3) to 10(5).
This study aims to evaluate the thermal characteristics of a biosourced insulation based on date palm waste and cardboard (cellulose) waste. The thermal insulation material based on date palm particles and cardboard can be integrated into a wall to improve the energy efficiency of buildings in the Errachidia city (City located in the South-East of Morocco). For this purpose, several samples were prepared separately from the packaging cardboard reinforced with the renewable parts of date palm fibers (petiole, trunk, cluster, pinnate leaves and mesh) with five mass fractions (40%, 50%, 60%, 70% and 80%). The thermal characterization method used is based on the principle of the high insulation thermal house. The results show that cardboard is a good thermal insulator and the addition of date palm waste has a positive effect on increasing the durability and mechanical resistance of our insulation.
In order to enhance local materials from the Drâa-Tafilalet region and more specifically the date palm waste. This work is an experimental contribution to the thermal characterization of wall mortar based on clay and date palm fibers. The aim is to experimentally evaluate the thermal insulation of samples made from earth mixed with date palm fibers from the Drâa-Tafilalet region (Errachidia Province). The total mass percentages of different date palm fibers (petiole fibers, pinnate leaves fibers, trunk fibers, palm cluster fibers and palm fibers mesh) are 20%, 30%, 40%, 50% and 60%. The thermal conductivity and density of the samples are determined experimentally. The thermal conductivity decreases as the percentage of fibers increases. However, the density decreases as the percentage of fibers increases. The samples made of clay with additives as the trunk or palm cluster fibers have a good insulating capacity compared to the other samples.
Aerosol optical properties are of high importance in understanding the evolution of radiative balance; they can also explain the atmospheric evolution and then the climate change. This study is focused on the data analysis of aerosol optical characteristics: aerosol optical depth, particle size distribution, aerosol radiative forcing and single scattering albedo registered by the network AERONET/PHOTONS for urban and desert sites .The monthly average of volume concentrations records larger amplitudes for fine and coarse mode for Ilorin (Nigeria) for which the total volume concentrations of an atmospheric column reach 424 10-3µm3 /µm2 and confirm the importance of urban aerosols. In other way, desert aerosol where coarse mode dominates like Tamanrasset registers 265 10-3µm3 /µm2. The seasonal cycle of optical thickness in visible and infrared show the highest values for the desert sites especially in spring and summer, a maximum reach 3,6 at Mezaira (UAE), These largest values are associated with the highest values of SSA in visible and infrared that reach 0, 93. The atmospheric radiative forcing seems with the same importance for both urban and desert sites, maximum reaches +84 W/m2 recorded in Tamanrasset (Algeria) and +79 W/m2 in Ilorin (Nigeria). The results confirm the warming tendency of the Atmospheric radiative forcing under both urban and desert sites.
This work is intended for comparative study the electricity production of a photovoltaic installation by using the monocrystalline silicon technology. The article is done in the frame of the Laboratory of Nanosciences and Modeling activities, for constructing a local productivity map of photovoltaic technologies by integration the theoretical calculation method and using the Pvsystem software. Our work is divided in two parts; the first is devoted to, calculating through MATLAB simulation the solar radiation at the site under study by using the hotel's method. And evaluate the final productivity of our mini-PV installation. In the second part we use the PVsystem software for prediction of a PV installation performance. Then we compare the results obtained by two methods of calculation; theoretical calculation method and by using the Pvsystem software.
This work aims at designing two Earth to Air Heat Exchangers (EAHX) for air cooling and heating of a primary school in Arfoud city Morocco, which is located in the South-East of Morocco and characterized by a desert climate. The school is constituted of two independent buildings. The Earth to Air Heat Exchangers should supply cool or warm air at a temperature of around 26°C and 20°C respectively. A total airflow rate of around 2000 m3/h is required for each building. The objective here is to identify the best EAHX parameters combination based on these requirements. For this purpose, a parametric study is performed using the well-validated TYPE 460 of TRNSYS software. Intermittent operation mode from 7 am to 6 pm during the school days (Monday to Saturday) is considered. The identification of the best combinations of the EAHX parameters is based on maximum and minimum EAHX exit temperature for cooling and heating purpose respectively, total cooling and heating capacity and the total pressure drop of the air inside the pipes. It was found that the best EAHX parameters combination is constituted of 4 pipes of 100 m length and 0.195 m internal diameter each buried at 5.7 m depth and operated at 4.63 m/s air velocity.
A computational method based on finite element method (FEM) is exploited to get accurate solutions of the equations describing the natural convection problem in a square cavity with differentially heated side walls having sawteeth at the bottom. A numerical investigation has been made for Rayleigh numbers ranging from 10 to 106.In addition, comparisons of the averaged Nusselt number with previous works for square cavity with flat bottom are realized in order to corroborate the numerical accuracy and the validity of our considered numerical problem.An excellent agreement with the previous results in the literature is attained. Further, the obtained results show the hydrodynamic effects of Rayleigh number and sawteeth at the bottom on both the fluid flow and the heat transfer inside the cavity.
This work investigates the impact of insulation measures on buildings energy consumption using infrared thermography as a fast and non-destructive tool to evaluate their thermal performance in situ. In this context, we have used this tool to assess this technique effectiveness in evaluating the insulation application on a residential building located in the city of Tangier in Northern Morocco. An experimental protocol was carried out in order to diagnose the studied building before and after the insulation application. Firstly, the different external surface temperatures of this building are used to estimate the in-situ heat transmission coefficient (U). The obtained U-values were then used in the Thermo-aeraulic modelling of the studied building under different interior and exterior climate conditions using the TRNSYS18-CONTAM environment.
In the sulfuric acid manufacturing process, Sulphur is burned to form Sulphur dioxide SO2 that then undergoes conversion to Sulphur trioxide SO3. The combustion happens in a large horizontal chamber which is a cylindrical vessel of carbon steel lined internally with refractory and insulation bricks. The chamber has two air inlets, one for primary air and another for the secondary one which is injected into the furnace after the initial combustion of Sulphur and is consumed in the conversion stage. The efficiency of this equipment is affected by scaling problems which may be caused by particle impurities inducted with liquid Sulphur in the inlet or caused by erosion of baffle walls. The present work contains CFD (Computational Fluid Dynamics) modeling and simulations of the hydrodynamic reacting flows in the furnace. The analysis and diagnosis of the CFD results have made it possible to determine the deep causes of those problems, which are mainly caused by the temperature gradients existing on both sides of the baffle walls. CFD results were validated against theoretical findings and recommendations have been proposed to improve the performance of the furnace.
The assembly of metal structures by welding is very developed in the industry, in particular the pressure vessels: boilers, tanks, etc. In the case of boilers that produce hot water and steam, it is very interesting to reduce heat losses in the welds. The objective of our work is to analyze the defects of the welded structures using two methods: phased array ultrasound and infrared thermography, and to evaluate the thermal losses.
In this work, we conducted a 2D study of stack flow in the presence of a downstream obstruction. This was done using a numerical simulation based on the finite volume method (FVM). The aim of this study is to study the effects of the variation of the wind speed on the ejected jet. The results obtained showed that this parameter has a large effect on the dispersion of the stacks and more important for the velocity ratio is large (R).
