Search results for "turbine"
showing 10 items of 198 documents
CFD simulations of dense solid–liquid suspensions in baffled stirred tanks: Prediction of solid particle distribution
2013
Abstract Industrial tanks devoted to the mixing of solid particles into liquids are often operated at an impeller speed N less than Njs (defined as the lowest speed allowing the suspension of all particles): under such conditions the distribution of solid-particles is very far from being homogeneous and very significant concentration gradients exist. The present work is devoted to assessing the capability of Computational Fluid Dynamics (CFD) in predicting the particle distribution throughout the tank. The CFD model proposed by Tamburini et al. [58] and successfully applied to the prediction of the sediment amount and shape was adopted here to simulate the particle distribution under partia…
Oscillation dynamics of free vortex surface in uncovered unbaffled stirred vessels
2016
Abstract The main feature of unbaffled stirred tanks is the highly swirling liquid motion, which leads to the formation of a central vortex on the liquid free surface, when the vessel is operated without top-cover (Uncovered Unbaffled Stirred Tanks, UUST). One of the main drawbacks of such vessels, that limits their industrial applicability, is the possible onset of low-frequency sloshing of the free surface. In this work, original data on oscillation dynamics in UUST are presented. In particular, data focus on the oscillation amplitude as well as on their frequency. Data were obtained by means of a novel experimental technique based on digital image analysis. The effect of impeller geometr…
Small Wind Technology Diffusion in Suburban Areas of Sicily
2015
Among renewable energy resources, wind energy became more attractive in the last decade. Wind farm installations dramatically increased in areas where climatic conditions, topography, and environment have allowed their development. The installation of wind turbines, usually carried out in remote areas, recently began to cover areas identified by a complex terrain such as urban and suburban zones. Although these new plant choices are characterized by lower productivity, there is increasing interest in wind energy production in both urban and suburban areas. In this work the authors have carried out an energy analysis developed from a sample of small wind turbines available on the market. Thi…
Modeling of a Smart Grid System Using Real Time Data οn Neplan
2013
The Institute for Energy and Transport (IET) is one of the seven institutes of the Joint Research Centre, which is a Directorate-General of the European Commission. IET is based both in Petten, the Netherlands, and Ispra, Italy, and has a multidisciplinary team of around three hundred academic, technical and support staff members. The mission of IET is to provide support to European Union policies in order to ensure sustainable, safe, secure and efficient energy production, distribution and use. The Energy Security Unit (ESU) is part of IET based in Petten and Ispra. A research action set up within this unit is devoted to studies on smart electricity systems (SES) and operates a Smart Grids…
Experimental characterization of a wind generator prototype for sustainable small wind farms
2016
This paper presents the experimental characterization of a wind turbine prototype used for micro wind farms. The proposed prototype, whose advantages can be summarized in versatility of application, low noise and compactness, can generate 1 kW of rated power for a wind speed equal to 4 m/s. The tests here reported and carried out by means of an experimental test bench confirm that the prototype is well designed and adequate for the purpose of its application.
Generalized feed-forward based method for wind energy prediction
2013
Abstract Even though a number of new mathematical functions have been proposed for modeling wind speed probability density distributions, still the Weibull function continues to be the most commonly used model in the literature. Therefore, the parameters of this function are still widely used to obtain typical wind probability density distributions for finding the wind energy potential by researchers, engineers and designers. Once long-term average of Weibull function’s parameters are known, then the probability density distributions can easily be obtained. Artificial neural network (ANN) can be used as alternative to analytical approach as ANN offers advantages such as no required knowledg…
Optimum Performance of Permanent Magnet Synchronous Generators Coupled to Wind Turbines
2007
In this paper a control algorithm for the efficiency improvement of permanent magnet synchronous generators (PMSG) is presented. The proposed algorithm reduces the losses of the generator without affecting its performances. In details, after a description of a dynamic model of the PMSG, which has been purposely modified in order to take into account the iron losses, the basic equations and the constraints to obtain the loss minimization are presented and discussed. Some simulations of a specific PMSG employing the proposed algorithm are performed. The results of these simulations show that enhancement of the efficiency up to 3% can be reached in comparison to a PMSG using a traditional cont…
Active power maximizing for Wind Electrical Energy Generating Systems moved by a Modular Multiple Blade Fixed Pitch Wind Turbine
2008
This paper proposes a new solution for wind electrical energy generating system (WEEGS). The system here taken into account is moved by a modular multiple blade fixed pitch wind turbine (MMBFPWT) and foresees a new MPPT algorithm whose main characteristics are low cost, low noise, buildings simplicity and modularity. The mathematical model of the entire WEEGS has been here developed taking into account all the components starting from the wind turbine and ending with the electrical grid. The WEEGS mathematical model has been implemented in Matlab-Simulink in order to carry out the simulations needed to test the effectiveness of the proposed WEEGS. The simulations results show the effectiven…
Sliding-mode observer based sensor-less control of a small wind energy conversion system
2015
Small wind turbines are becoming an attractive solution for household applications. These micro generation units can be used as standalone applications or grid connected applications. However to get the full potential benefits of these wind turbines, systems should be low cost and reliable. Introducing the wind speed and rotor speed sensors at the generator shaft may reduce the reliability of small wind turbines. In this study, a grid connected sensor-less 5 kW small wind energy conversion system has been studied. The maximum power point tracking method of the wind turbine is totally independent from wind speed and rotor speed measurements. Optimum rotor speed and actual rotor speed are est…
Assessment of the technical and economic potential of offshore wind energy via a GIS application: A case study for the Sicily Region according to Ita…
2015
This paper presents a technical and economic analysis of the possible exploitation of offshore wind resources using spatial analysis methods based on GIS tools. The study assessed the magnitude and distribution of the main constraints on installation of wind farms by taking into account the relevant technical factors and local laws on nature protection issues in a specific area, i.e., Sicily. Specific cost functions were defined for several components of the total cost of construction and maintenance of a wind farm. Several scenarios were implemented according to wind turbine size, hub height, total wind farm power, and distance from the coast, and the levelised production cost was assessed…