M. BAKRI Badis

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Understanding flashover voltage and leakage current is crucial for evaluating and ensuring the performance, reliability, and safety of high-voltage insulators in electrical networks. Investigating the flashover process and leakage current is significant because it helps to understand the behavior of insulators under different conditions, such as desert pollution. The objective of our study is to create a circular model that accurately simulates the real functioning of a 1512 L high-voltage insulator. This particular insulator is widely utilized by the algerian power and gas company (SONELGAZ), contributing significantly to the comprehension of its operational principles. In our current work, we aim to investigate the effect of conductivity and the distribution of discontinuous contamination on insulator behavior and its response within an intentionally contaminated experimental model. Additionally, we aim to incorporate previous insights regarding the severity of contamination at specific locations. Our ongoing research relies on observations and various measurements obtained from flashover voltages and leakage currents. Through this model, researchers can comprehensively evaluate insulator performance under diverse conditions, facilitating a deeper understanding of their behavior. The analysis of the results obtained from numerous tests conducted in the high-voltage laboratory of the University of Biskra, Algeria, forms the basis of our study.

A solar air heater is a device that gathers solar radiation and converts it into heat. The core principle involves air moving through a solar collector, where sunlight naturally increases the air temperature within the collector. The benefit of this technology lies in its affordability and simplicity. The implementation of a solar air heater (SAH) test bench holds significant promise in addressing both global change and sustainable development objectives. The primary goal of this study is to examine the aerodynamic configuration of a novel solar air heater test bench accessible at the Laboratory of Electro-Mechanic Systems (LASEM). This study was carried out using the standard k-ω turbulence model with the use of the ANSYS Fluent 17.0 software. The results indicate that the velocity at the inlet directly influences the velocity fields, temperature, static pressure, and characteristics of turbulence. Furthermore, the numerical findings confirmed that the temperature and velocity profiles in the second channel are in good concordance with the experimental findings in the case of a fan, placed alongside the insulation, operating in a delivery mode. Based on these results, the computational approach is validated. When comparingforced convection to natural convection under identical conditions, there was a notable increase in the energy efficiency, with forced convection showing a significant improvement of approximately 31.8%. Indeed, the range of temperatures reached with the proposed design, is highly beneficial for both industrial and household applications.

The aim of this work is to estimate the flashover voltage of a high-voltage insulator that has been deliberately polluted using fuzzy logic
(FL). Initially, experimental experiments on a high-voltage insulator were used to collect a data set that was then used to implement the idea of
artificial intelligence. These studies were conducted using varying degrees of fake pollution, namely saline distilled water. Each pollution level
indicated the quantity of artificial pollution, measured in millilitres, in each section of the insulator. The collecting database provides flashover voltage
measurements associated with varying levels of artificial pollution in each insulator zone and its conductivity. Furthermore, we have used fuzzy logic
(FL) to forecast the flashover voltage of the high-voltage insulator and assess the insulating condition of simulated pollution. The suggested
prediction model, which is based on Federated Learning (FL), is implemented using MATLAB's graphical user interface. Ultimately, a comparison
was conducted between the outcomes achieved by FL and real-world ones. The database used in this comparison differs from that used in concepts
based on programming language implementation taken from previous literature. The findings demonstrate the superior effectiveness of the FL
approach in predicting the flashover voltage of high-voltage insulators when compared to data acquired from practical testing

The orthophosphates materials are one of the most important groups in the field technologically advanced materials that are accessible, inexpensive, and environmentally friendly. This materials are of great demand due to their various optoelectronic applications in recent years. In this study, a solid-state method was employed to synthesize the AgCoPO4 orthophosphate sample. Analyzing the XRD pattern, of the studied compound, confirms the triclinic phase with the
space group. The examination of SEM analysis and energy dispersive spectroscopy (EDS) revealed the same morphology and different particle sizes. As for the EDX analysis, all chemical elements were detected and found in their appropriate ratio. Besides, the impedance spectroscopy measurements conducted at 100 Hz to 5 MHz and 473–673 K are used to investigate the electrical and dielectric properties of the AgCoPO4 compound. The frequency dependence of the conductivity of alternating current is explained using Jonscher’s law. The calculated activation energy is in accordance with Arrhenius’s behavior based on DC conductivity, which was determined to be 0.93 (2) eV. The primary transport mechanism is governed by the correlated barrier hopping model. A comparative study of impedance and modulus responses versus frequency suggests Cole–Cole behavior. deep investigation of the electric and dielectric performances demonstrated a significant dielectric constant (ε′ ∼ 104) at low frequencies and low dielectric loss at high frequencies. Thus, it highlights its exceptional dielectric potential, particularly in applications related to electronic capacitors.

The chimney junction of solar chimney power plant was the main element coupled the solar collector to the chimney. It presents an important impact on the SCPP design, which is change the air-flow direction. The numerical code ANSYS Fluent was used in this study to investigate how the chimney Junction radius affected the local air-flow characteristics and the turbine site. Using test results from an experimental prototype constructed in Sfax, Tunisia, the numerical method was validated and verified. For four set-ups with various chimney connection radii, thermodynamic variables such as distributions of the total pressure, static temperature, static pressure, and magnitude velocity were examined. Also, the influence of these parameters on the air turbulence was analyzed through the transition zone. The results showed that the local air-flow characteristics and therefore, the SCPP efficiency were significantly impacted by changes in junction radius. Besides, the maximum velocity inside the chimney was varied and changes its location when the junction radius changed. These facts affect directly the overall turbine expenditure, which represented in terms of structure and power capacity.

Abstract: This paper is intended to check the thermal convection flow during a new solar air heater (SAH) test bench, which is conducted in the LASEM laboratory. In fact, the applied system includes a two-passage heater solar air separated by an absorber. On the other hand, a glass piece is connected to the box prototype via a pipe. The study was conducted using the Navier-Stokes equations associated with the k–ω turbulence model through the use of Ansys 17.0 software. Based on our experimental results generated in a two-passage solar air heater connected to the box prototype, the computational approach and the simulation results were validated.

Abstract

The main insulation layer is the most important layer of the high-voltage cable, and the quality of this material directly affects the life of the cable. It is also known that Heterogeneous cavities associated partial discharges in the insulation can affect the service life of cables. In this paper, we use the COMSOL Multiphysics software, which is based on the finite element method in AC/DC, 2D electrostatic. Heterogeneous cavities, such as bowtie water trees, vented cavities, and air void cavities, are easily damaging to XLPE power cables. This paper studies the electrical constraints within an XLPE-insulated cable containing micro-cavities. Due to the possibility of partial discharge (PD), it is crucial to be aware of the existence of heterogeneous cavities in insulating materials before using them as cable insulation. This study examines the impact of having such diverse voids in the insulation of high-voltage cables. Additionally, using the COMSOL tool, the impact of altering the cavity's position and size on the PD behavior under various operating circumstances was examined. The obtained results are in good agreement.

Abstract

One of the world's oldest renewable energy sources is solar energy, which may be easily harnessed to lessen dependency on energy derived from hydrocarbons and is readily available. Data on solar radiation are crucial for the planning, development, and operation of energy and renewable energy systems. Numerous considerations had a role in the decision to locate the solar power plant in Ain El-Melh. First and foremost, the site's accessibility was essential since Ain El-Melh is near transportation hubs, making it simple to relocate workers and construction equipment. Solar irradiance is necessary to calculate several aspects of system performance connected to the sun, such as the size and efficiency of renewable energy systems. The objective of this study is to use real meteorological data to develop an artificial neural network-based forecast model for the Ain El-Melh region. The results allowed for the selection of this approach because of its advantages that were specific to the problem at hand.

Abstract Heterogeneous cavities, such as bowtie water trees, vented cavities, and air void cavities, are easily damaging to XLPE power cables. This paper studies the electrical constraints within an XLPEinsulated cable containing micro-cavities. Due to the possibility of partial discharge (PD), it is crucial to be aware of the existence of heterogeneous cavities in insulating materials before using them as cable insulation. This study examines the impact of having such diverse voids in the insulation of high-voltage cables. Additionally, using the COMSOL tool, the impact of altering the cavity's position and size on the PD behavior under various operating circumstances was examined. The obtained results are in good agreement.

Abstract One of the most important power quality problems, current harmonics has generated a lot of study attention. The greatest way to reduce harmonic contamination is to use a shunt active power filter (SAPF), however, its efficiency is entirely reliant on how quickly and precisely its control algorithms can work. This study investigates the functioning of a four-wire shunt active power filter (SAPF) under unbalanced load situations using a simulation of a three-phase four-wire shunt active power filter (SAPF) decreased current measurement control technique caused by nonlinear loads. The suggested method for correcting the load's reactive power and harmonic currents is effective, according to simulation results produced by Matlab/Simulink.

Abstract: The spectrum irradiance must be measured because different sunlight wavelengths (or colors) are absorbed in various regions of our atmosphere. Calculating different sun-related system performance, such as the size and performance of renewable energy systems, requires knowledge on solar irradiance. The goal of this work is to create a forecast model based on artificial neural networks in the M'sila area using actual meteorological data. The outcomes made it possible to choose this strategy due to its benefits that were tailored to the issue at hand.

In this chapter, we are interested on the design and the realization of a
new solar air heater test bench to investigate the efficiency of the solar
system. The considered test bench consists of two passages solar air
heater separated by an absorber and powered by a fan working in a
delivery mode. On the glass side, it is connected to the box prototype
through a pipe. On this system, a glass is hanging on the front side and
an absorber is inserted inside. The hot air flow is routed towards the box
prototype. Two circular holes are located in the same face of the box
prototype. The inlet hole allows the hot air supply. However, the outlet
hole allows its escape into the ambient environment. Indeed, we have
developed numerical simulations to study the turbulent flow in the
considered test bench over the day. In these conditions, it has been
observed a decrease in the flow and an appearance of the recalculation
zones in the first passage. This phenomenon is more prominent during
the transition of the flow to the second passage. However, the flow
becomes uniform until the exit of the solar air heater. Via the pipe
separating the solar air heater from the box prototype, a discharge area
appears in the hole inlet and invaded the reverse wall. By comparing the
local characteristics for the different instances, a similar appearance has
been observed with a maximum value at t=12 hours. For the magnitude
velocity, a small difference between the calculated values has been noted.
However, this difference is more clear for the temperature distribution
and the turbulent characteristics. For the energy efficiency, it presents
very low values at the beginning of the day. With the increase of the
temperature through the day, there is a gradual increase of the energy
efficiency until t=12 hours, with a value equal to η= 31,8%. This
technology will be very useful since it can provide sustainable energy
and substitute the expensive traditional technologies.

Support de cours : TP physique 2 (ST)

ABSTRACT
In this paper, we use the comsol multiphysics software, which is based on the finite element method in AC/DC 2D electrostatic. Our study shows the effect of heterogeneous cavities on the functioning of electrical cables. Our mini-project contains the study of electric field distribution and potential of a model of high voltage cable; we took into account the absence and the presence of heterogeneous cavities. The study was conducted using numerical results with mathematical validation. The results are favorable and promising.

Solar chimney power plants are passive thermal systems that use the greenhouse effect to produce electricity from solar radiation (SR). The performance of these devices varies from one climate to another. Indeed, the building site of the SCPP is a particular parameter for its total effectiveness. The aim of this work was to present an experimental investigation of a solar chimney prototype under the climatic conditions of Sfax, Tunisia. In fact, Sfax is characterized by its arid and sunny climate. The impact of the climatic conditions of Sfax city on the aero-thermal characteristics of the considered prototype is carried out. Particularly, the variations of the fluid temperature and velocity are carried out under different times. The present outcomes show that the solar chimney power plant is an applicable device in the Tunisian region of Sfax.

In this chapter, the impact of the numerical parameters on the heat
ventilation was studied in a box prototype. Particularly, a computational
study and an experimental validation have been developed to compare
the standard k-ω turbulence model, the BSL k-ω turbulence model, the
SST k-ω turbulence model, the standard k-ɛ turbulence model, the RNG
k-ɛ turbulence model and the Realizable k-ɛ turbulence model. From the
obtained results, it is noticed that the aerodynamic characteristics present
the same emergence nevertheless the maximum values depend on the
turbulence model. Particularly, it has been noted that the value founded
with the standard k-ω turbulence model is nearest to the experimental results.
This study tends to show that the standard k-ω turbulence model
is the most efficient to study the air flow in the box prototype. For this
model, the meshing effect on the CFD results was studied to choose the
adequate mesh with a minimum calculated time. The numerical results
were compared using experimental results developed in our laboratory.
The good agreements confirm the numerical method.

Knowledge of solar irradiance is essential for calculating various solar-related system performance, such as sizing and performance of renewable energy systems. The objective of this work is to develop a prediction model from real meteorological data which is based on artificial neural networks in the M'sila region. The results obtained made it possible to opt for this technique for its advantages adapted to the posed problem.

Energy production represents a significant challenge in the years ahead. Indeed, the energy needs of industrialised companies continue to grow. As well, the countries developing countries will require more and more energy to complete their mission development. The danger, excess use of natural resources is decreasing reserves of this type of energy in a way that is dangerous for future generations.. Today, energy security is the triggering factor for a developing country. Thus, for ensuring energy security renewable energy such as PV plant could be the best alternative. The objective of this work is to develop a prediction model from real meteorological data which is using response surface methodology in the M'sila region. The results obtained made it possible to opt for this technique for its advantages adapted to the problem posed.

Solar radiation predictions are important to achieve our work goals. In this work, the main goal is to propose an algorithm
that can be used to predict solar irradiance. Using a dataset consisting of temperature, humidity, wind speed, air pressure, and solar
radiation data, an artificial neural network (ANN) model was constructed to efficiently predict solar radiation in the Thira region
using the available weather forecast data based on the artificial neuron prediction network in M’sila region. The results obtained
made it possible to choose this technique because its advantages fit the problem posed.

This paper is intended to check the thermal convection flow during a new solar air heater (SAH) test bench, which is
conducted in the LASEM laboratory. In fact, the applied system includes a two-passage heater solar air separated by an absorber. On
the other hand, a glass piece is connected to the box prototype via a pipe. The study was conducted using the Navier-Stokes equations
associated with the k–ω turbulence model through the use of Ansys 17.0 software. Based on our experimental results generated in a
two-passage solar air heater connected to the box prototype, the computational approach and the simulation results were validated.

This paper is intended to check the thermal convection flow during a new solar air heater
(SAH) test bench, which is conducted in the LASEM laboratory. In fact, the applied system includes
two-passage heater solar air separated by an absorber. On the other hand, a glass piece is connected
to the box prototype via a pipe. Then, the piece of the glass is attached to the front side of this
device in which an absorber is inserted. Moreover, two circular holes are made on the same face of
the box prototype. The first is an entry hole through which hot air goes inside, and an exit hole
through which air is released into the surrounding area. The study was conducted using the Navier-
Stokes equations associated with the k–ω turbulence model through the use of the newly released
Ansys 17.0 software to characterize the aero-thermal structure of our new system operating in
natural convection. In these conditions, it has been observed that the hot zone created on the mirror
side receiving the solar radiation generates an ascendant movement. It goes from the bottom to the
top and enters the box prototype. The same phenomenon is also created in the box where the airflow
coming from the solar heat escapes into the environment. This movement created between the hot
zone of the solar heat and the box prototype is also imposed in the cold zone of the solar heat on the
heat-insulating side. In these conditions, the air movement is however from the top to the bottom.
Indeed, the acceleration of the air velocity at the inlet of the solar heat is due to the change of the
section which is more reduced by comparison to the rest of the air circulation duct. Based on our
experimental results generated in a two-passage solar air heater connected to the box prototype, the
computational approach and the simulation results were validated. By referring to the classic solar
air heater with one passage, the energy efficiency measured in the same conditions was enhanced
and presented the efficient one with an improvement of about 27%. Finally, the numerical results
are compared to our experimental results and those obtained by the authors. The comparison proved
a good agreement.

The solar air heater is a system which collects the radiation and transforms it into heat. The general idea is that the air is flowing through the solar collector and heat from the sun naturally raises the temperature of the air inside the collector. The advantage of this technology is that it is cheap and simple. The main objective of this work is to investigate the aerodynamic structure of the turbulent flow in a new solar air heater test bench, available in our LASEM laboratory. By using the ANSYS Fluent 17.0 software, the analysis was performed using the Navier-Stokes equations coupled with the standard k-ω turbulence model. The computational method and the simulation results were validated based on our experimental results developed in a tow passage solar air heater connected to a box prototype. The range of temperatures is very useful in industrial and domestic applications. The obtained results will be considered to produce better comfort conditions in case of supplying rooms.

The solar air heater (SAH) is a widely used thermal application of renewable energy. This paper studies experimentally the unsteady turbulent flow in a new SAH test bench developed in the LASEM laboratory, was investigated. The used test bench is composed by two passages separated by an absorber and powered by a fan working in a delivery mode, placed in the inlet side the insulation, for the forced convection mode. Two circular hole, are located in the face of the box prototype. The inlet hole allows the hot air supply. However, the outlet hole allows its escape into the ambient environment. The results predicted by CFD simulation used the Navier-Stokes equations coupled with the standard k-ω turbulence model were resolved. Comparisons with experimental data have been performed and found to be in excellent agreement. This work will promote technique devel-opments of solar air heater.

Investigations of the flow in a building system are crucial for understanding the fundamental basis of the aerodynamic structure characteristics. The CFD simulations were conducted using ANSYS Fluent 17.0 software, which solves the Navier-Stokes equations in conjunction with different turbulence models and by a finite volume discretization method. Particularly, a comparison between the experimental and standard k-ω, BSL k-ω, SST k-ω, standard k-ɛ, RNG k-ɛ and Realizable k-ɛ turbulence model has been developed. The comparison between the founded results affirms that the standard k-ω turbulence model is the most efficient to model the air flow in the present application. Indeed, the numerical results compared using the experimental data developed in the LASEM laboratory confirms the validity of the numerical method. The good agreements validate the considered computational method.

In this work, the unsteady turbulent flow in a new solar air heater test bench, developed in our LASEM laboratory, was predicted. The considered system consists of two passages solar air heater separated by an absorber and powered by a fan working in a delivery mode, placed in the hole inlet side the insulation. On this system, a glass is hanging on the front side and an absorber is inserted inside. On the glass side, it is connected to the box prototype through a pipe. The hot air flow is routed towards the box prototype. Two circular holes, are located in the same face of the box prototype. The inlet hole allows the hot air supply. However, the outlet hole allows its escape into the ambient environment. By using the ANSYS Fluent 17.0 software, the Navier-Stokes equations coupled with the standard k-ω turbulence model were resolved. The numerical results were compared with our experimental data, established in the second passage of the solar air heater test bench. The good agreement confirms the validity of the numerical method. The range of temperatures is very useful in many applications such as industrial and domestic applications.

Looking through the current global economic context, energy efficiency in all its aspects should be part of our consciousness. This study deals with the influence of the turbulence model on the numerical results. The results of simulations and experiment were mutually compared. The analysis was performed using 3D steady Navier-Stokes governing equations were solved using the software ANSYS Fluent 17.0. Computational Fluid Dynamics (CFD) simulations with different turbulence models are applied to evaluate the performance of three turbulence models the standard k-ω turbulence model, the BSL k-ω turbulence model, and the SST k-ω turbulence model. The present study confirm that the standard k-ω turbulence model can be recommended for related types of applications. The good agreement between the numerical results and our experimental data developed in the LASEM laboratory confirms the validity of the numerical method.

Abstract

Several investigators studied the natural convection heat transfer in tow passage solar air heater connected to a box prototype and much useful information is available in the literature. The use of the solar air collector is an effective technique to enhance the heat transfer to fluid flowing in the box prototype. In the present paper, we have developed numerical investigation of the natural convection flow in a new solar air heater test bench with two passages. By using the ANSYS Fluent 17.0 software, the analysis was performed using the Navier-Stokes equations coupled with the standard k-ω turbulence model. Based on the developed results, solar radiation has been found to be the main parameter which characterizes the thermal behavior of the system. Besides, exergy analysis has been carried out, and optimum conditions in which the system has the highest performance have been determined.

The flashover of pollution, observed on the insulators used in high voltage transmission, is one of the most important power transmission stakes. It is a very complex problem due to several factors including the modelling difficulties of complex shapes of insulators, different pollution densities at different regions, non-homogeneous pollution distribution on the insulator surface and unknown effect of humidity on the pollution. In the literature, some static and dynamic models have been developed by making some assumptions and omissions to predict the flashover voltages of polluted insulators.
This paper aims to experimentally analyse the flashover process and simulation of the distributions of the potential and the electric field under 50 Hz applied voltage on a real model simulating the 175CTV outdoor insulators largely used by the Algerian Company of Electricity and Gas (SONELGAZ). This real model is studied under non-polluted (distilled water), and polluted (distilled water and sand) environments. The simulations were carried out by using the COMSOL multiphysics software. This program uses the finite element method to solve the partial differential equations that describe the field. Experimental results made in the laboratory and simulation results are original and found to be congruent.

This paper investigates the unsteady state of the heat ventilation in a box prototype with two holes. The CFD
simulations were conducted using ANSYS Fluent 17.0 software, which solves the Navier-Stokes equations in
conjunction with the standard k-ω turbulence model and by a finite volume discretization method. The presented
results, consisting of the distribution of the velocity fields, the temperature, the total pressure and the
turbulent characteristics, are very useful to determine the time required for the heating operation and to shrink
the energy consumption of the buildings. The comparison between the founded results affirms that the heating
time presents a straight effect on the velocity fields. However, for the temperature, the box prototype requires
more time and more energy to warm up. In our application, we confirm that the duration of 30 s is sufficient to
allow the heating of the box prototype. Indeed, the numerical results compared using the experimental data
developed in our laboratory confirms the validity of the numerical method. The good agreements validate the
considered computational method.

Improving air quality can support efforts to mitigate climate change. The challenge that we are facing is, therefore, to
ensure that our air and climate policies focus on win-win scenarios. For this, we have studied the heat convection flow in a new solar
air heater test bench, available in our LASEM laboratory. By using the ANSYS Fluent 17.0 software, the analysis was performed
using the Navier-Stokes equations coupled with the standard k-ω turbulence model. The computational method and the simulation
results were validated based on our experimental results developed in a tow passage solar air heater connected to a box prototype.
The range of temperatures is very useful in many applications such as industrial and domestic applications.

The use of efficient systems in order to reduce the energy consumption presents in nowadays a great challenge. Indeed, the use of the renewable energy in the heat ventilation of building application becomes very crucial. In this work, we are interested on the study of the turbulent flow in a box prototype. In this prototype, a solar system is integrated to supply the whole inlet with a hot air. The numerical model is based on the resolution of the Navier-Stokes equations in conjunction with the standard k-ω turbulence model. These equations were solved by a finite volume discretization method using the commercial CFD code ANSYS Fluent 17.0. To accurate the numerical results, the meshing effect on the numerical results was studied to choose the optimal mesh with a minimum calculated time. The numerical results were compared using anterior results developed in our laboratory. The good agreements confirm the validity of the numerical method.

In this work, the turbulent flow was studied in a new SAH (solar air heater) test bench. Particularly, we
have considered the natural and the forced convection modes. The used test bench is composed by two
passages separated by an absorber and powered by a fan working in a delivery mode, placed in the inlet
side the insulation, for the forced convection mode. On this system, a glass is hanging on the front side
and an absorber is inserted inside. On the glass side, it is connected to the box prototype through a pipe.
The hot air flow is routed towards the box prototype. Two circular holes, are located in the same face of
the box prototype. The inlet hole allows the hot air supply. However, the outlet hole allows its escape into
the ambient environment. By using the ANSYS Fluent 17.0 software, the Navier-Stokes equations coupled
with the standard k-u turbulence model were solved. The numerical results were compared with our
experimental data, established in the second passage of the SAH test bench. The good agreement confirms
the validity of the numerical method. The range of temperatures is very useful in many applications
such as industrial and domestic applications.

In this work, the structural, electronic and optical properties of fluoroperovskite ABF3 (A = K, Na; B = Mg,
Zn) were studied using two different approaches: the full-potential linearized augmented plane wave method and the
pseudo-potential plane wave scheme in the frame of generalized gradient approximation features such as the lattice
constant, bulk modulus and its pressure derivative are reported. The ground state properties of these compounds such as the
equilibrium lattice constant and the bulk modulus are in good agreement with the experimental results. The first principles
calculations were performed to study the electronic structures of ABF3(A = K, Na; B = Mg, Zn) compounds and the
results indicated that these four compounds are indirect band gap insulators. The optical properties are analysed and the
source of some peaks in the spectra is discussed. Besides, the dielectric function, refractive index and extinction coefficient
for radiation up to 25 eV have also been reported and discussed.

Solar air heater is a type of solar system which collects solar energy and transforms it into heat. The general idea is that
the air is flowing through solar collector and heat from sun naturally raises the temperature of the air inside the collector. The
advantage of this technology is that it is cheap and simple. The main objective of this work is to design and build a solar air heater
test bench in order to make an experimental study for different modes of functioning. We test almost three configurations, forced
convection and natural convection in case of open loop functioning. We test also the closed loop where the solar air heater is
supplying a test box. From this study, we can conclude that in case of a forced convection the glass side delivery is the most efficient
mode especially in case of high ambient temperature. Insulation side delivery is also efficient but in case of low ambient temperature.
For the natural convection, we can reach high outlet temperature. Indeed, we interested in the jet near the ducts and we studied the
distribution of the temperature and the velocity inside the box. We can confirm that the temperature and the velocity need certain
distance to stabilize about 0.7 m in our prototype. The range of temperatures is very useful in many applications such as industrial
and domestic applications. The obtained results will be considered to get better comfort in case of supplying rooms.

This paper presents the results of the CFD simulations of the flow inside a box prototype with two openings. In this work, we are interested in the study of the heat ventilation of a box prototype with a k-ω turbulence model. In this work, we have conducted simulations on simple and distinct geometries using ANSYS Fluent 17.0 software. The unsteady flow of natural ventilation with is analyzed and the temperature with respect to time is investigated. Finally, a number of conclusions are derived about the simulation process, the function of natural ventilation and the thermal comfort of the space in corresponding cases.

Abstract

Investigations of the flow in a building system are of importance for understanding the fundamental basis of their aerodynamic structure characteristics. The study of the turbulence in the vicinity of an isolated building is very crucial. For thus, the heat ventilation and thermal comfort evaluation in a living room was developed using the ANSYS Fluent 17.0 software. The analysis was performed using 3D steady Naviere-Stokes Computational Fluid Dynamics (CFD) simulations with different turbulence models. The computational analysis and the simulation results are validated based from the anterior results developed in our LASEM laboratory.

In this paper, we are interested in studying of the turbulent flow in a buildings and environmental parameters associated with a known system. In fact, the designer must now meet the requirements of functionality, comfort and design, but also environmental sustainability and energy efficiency. In this work, we have conducted simulations on simple and distinct geometries using ANSYS Fluent 17.0 software. In particular, we are interested on the study of the meshing effect on a simple geometry, to choose the optimal mesh with good simulation results with a minimum calculated time. The numerical results are validated using anterior results founded from the literature.

Abstract

Wehaveperformedfirst-principlecalculationsofthestructural,electronicandmagnetic
properties ofceriummanganeseoxide(CeMnO)3, usingfull-potentiallinearizedaugmen-
ted plane-wave(FP-LAPW)schemewithinGGAandGGAþU approaches. Featuressuchas
the latticeconstant,bulkmodulusanditspressurederivativearereported.Also,wehave
presented ourresultsofthebandstructureandthedensityofstates.Theresultsshowa
half-metallicferromagneticgroundstateforCeMnO3 in GGAþU treatment,whereas
semi-metallicferromagneticcharacterisobservedinGGA.Theresultsobtained,makethe
cubic CeMnO3 a candidatematerialforfuturespintronicapplication.