Study of the meshing effect on the numerical results of a NACA2415 airfoil wind turbine

In this work, we are interested on the study of the meshing effect on the numerical results developed using a commercial CFD code based on the resolution of the Navier-Stokes equations in conjunction with the standard k-? turbulence model. The developed numerical method is used to study the aerodynamic structure of a horizontal axis wind turbine with a NACA2415 airfoil type. The developed numerical results are compared with experimental results conducted on an open wind tunnel to choose the adequate numerical model

Étude expérimentale des performances d´une éolienne à axe vertical de type Savonius à différents recouvrements externes

Une investigation expérimentale s’intéressant à l’étude d’une éolienne à axe vertical de type Savonius à différents recouvrements externes est entamée. Ce travail a nécessité la fabrication du rotor Savonius en plexiglace et sa fixation dans la veine d’essai d’une soufflerie aérodynamique de type aspiration. Une instrumentation spécifique a permit également la détermination des caractéristiques globales de l’éolienne dans les différents montages considérés. Il s’agit en fait de modifier le recouvrement externe mesuré entre les deux voilures dans un plan contenant les bords d’attaque du rotor Savonius. Les résultats expérimentaux présentés consistent essentiellement à déterminer l’évolution des coefficients adimensionnels de la puissance et du couple en fonction de la vitesse d’écoulement de l’air dans la veine d’essai

Effect of heat flow via glazing on the productivity of a solar still

In many parts of the world, particularly in the Greater Maghreb, desalination of water by solar energy is practiced with incredible abundance. Drinking water shortage has become a major problem. Improving the efficiency of solar distillers in several laboratories around the world is still one of the major concerns of research topics. In this work we want to show that the heat flow through the glazing can also be considered as an index on the productivity of pure water from a conventional solar still

Induction machines diagnosis by the time's harmonics

The induction motor is currently becoming the key element of most industrial equipment. Despite these advantages, a certain number of constraints of very different natures can affect the lifetime of this machine, causing considerable economic losses. This work is the study experimental of defects for an asynchronous machine  (with and without defect). After having described the main defects that can occur on these. In this study,  we propose a method called induction machines diagnosis by the time's harmonics. This technique is based to study the influence of a defect of short-circuiting on the studied induction motor, we will find the rank of the harmonic of the most influenced by the number of the rank default. this study will find the diagnostic index of induction motor with stator default using the time harmonics. The results obtained show that the 3rd order time-harmonic is very sensitive compared to the other harmonics

Comparative study of advanced techniques for the diagnosis of induction motors

This work is a comparative study between the various advanced technologies of diagnosis of induction motors published recently and to make a classification of these diagnostic techniques according to their sensitivities from experimental results of stator short-circuit faults between stator turns. By using the logarithmic FFT spectrum, we can discover the best method to detect faults in their early stages so that we can predict their faults and anticipate breakdowns that can be dangerous for people or the economy

Effect of using sponge pieces in a solar still

Solar distillation is a very effective way to obtain pure water, especially in isolated areas where the water is infected or polluted to obtain drinking water. Two conventional solar stills of the same size (0.5 x 0.5 m) were tested for 8 hours. One still is priced as an SSR reference still and the other still which contains pieces of sponge is SSM and that is the subject of our work. The results show that the use of sponge in winter improves the yield of 10 %

Developed nonlinear model based on bootstrap aggregated neural networks for predicting global hourly scale horizontal irradiance

This research study examines the use of two models of artificial intelligence based on a single neural network (SNN) and bootstrap aggregated neural networks (BANN) for the prediction value of hourly global horizontal irradiance (GHI) received over one year in Tamanrasset City (Southern Algeria). The SNN and BANN were created using overall data points. To improve the accuracy and durability of neural network models generated with a limited amount of training data, stacked neural networks are developed. To create many subsets of training data, the training dataset is re-sampled using bootstrap re-sampling with replacement. A neural network model is created for each set of training datasets. A stacked neural network is created by combining multiple individual neural networks (INN). For the testing phase, higher correlation coefficients (R = 0.9580) were discovered when experimental global horizontal irradiance (GHI) was compared to predicted global horizontal irradiance (GHI). The performance of the models (INN, BANN, and SNN) demonstrates that models generated with BANN are more accurate and robust than models built with individual neural networks (INN) and (SNN)

Effect of the Preheating Inlet Air on the G222 Fuel Combustion

In this paper, a numerical simulation is developed to study the preheating effect of the air in a three-dimensional cylindrical combustion chamber using the FLUENT-CFD code. Particularly, we are interested on the calculation of the characteristic parameters such as the axial velocity, the temperature and the mass fraction of carbon monoxide. This study consists of a special treatment of mathematical models. The considered approaches resolve the governing equations of system. The main objective of this work is to study the behavior of the parameters considered previously during the variation of the air inlet temperature. The obtained results show that the variation of the inlet temperature presents a direct effect on the considered parameters.

Influence of types of nanoparticles, nanoparticles volume concentration and types of cooler metals on the heat transfer in a mini-channel cooler

In the present work, we have studied the effect of three different types of nanoparticles, nanoparticles volume concentration and types of cooler metals on heat transfer in a mini channel cooler numerically. In these simulations, we have considered the Cu-H2O, the Ag-H2O and the Diamond-H2O with different volume fractions in the range of 0,02%-0,1% and for two types of cooler materials for cooling an electronic component. In these conditions, the inlet velocity is constant for the three different types of nano-fluids. The power of the electronic component is equal to 130 W. The numerical results are developed for a Reynolds number equal to 1414 and a steady-state. The simulation was performed using commercial software, ANSYS-Fluent 15.0. The obtained results show that the average heat transfer coefficient increases with the increase of the volume fraction of the nanoparticles (Cu, Ag, Diamond) and with the decrease of the temperature of the electronic component. In these conditions, the average heat transfer coefficient is the highest for the H2O–diamond nanofluid compared with the other nanofluids the Cu-H2O and the Ag-H2O. Furthermore, the types of cooler metals have considerable effects on the amelioration of the temperature of the electronic components