Examinando por Materia "TURBINAS"
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Ítem Caracterización experimental de la pérdida rotacional (Rotating Stall) en una bomba centrífuga operando como turbina(Universidad EAFIT, 2016-03-14) Pérez Mesa, Jesús Alberto; Botero Herrera, Francisco JavierÍtem Experimental rotordynamics and flow visualization approach for periodically reversed flows of a Francis - Type Pump - Turbine in generating mode at off - design operating conditions(Universidad EAFIT, 2012) Guzmán Díaz, Sebastián; Botero Herrera, Francisco JavierA non-conventional tufting visualization method along with an image processing development and specific applied technique adapted to the flow conditions is proposed and implemented on a reduced scale model of a Francis-type reversible pump-turbine in three different turbine stages such as turbine mode, runaway mode and turbine break mode, in order to visualize rotating stall phenomenon -- Fluorescent monofilament wires along with high speed image processing and pressure sensors were installed in the narrow and vane less gap between the impeller blades and guide vanes -- Pressure fluctuations were analyzed along with tuft visualization to describe the flow with and without rotating stallÍtem Management des risques basé sur la logique floue pour la maintenance d’une turbine Francis(Universidad EAFIT, 2008) Tobón Mejía, Diego Alejandro; Botero Herrera, Francisco JavierPour faciliter la maintenance de groupes hydroélectriques et assurer la production en énergie électrique, nous avons défini un outil d’aide à la décision pour la définition de plans de maintenance en intégrant la notion de risques pour une turbine Francis actuellement en activité dans une centrale hydroélectrique en Colombie -- La difficulté majeure en gestion des risques est la quantification des risques les uns par rapport aux autres, quantification essentielle pour que les actions de maintenance mises en place assurent à la fois la disponibilité du système et la sécurité de l’ensemble -- Les risques étant généralement exprimés en terme de connaissance humaine, il nous a semblé très intéressant d’utiliser la logique floue pour résoudre ce problème -- Le travail mené nous a permis de constater que la logique floue se présente comme une méthode très prometteuse -- De plus, elle peut aussi bien s’appliquer dans le cas de défaillances détectables (grâce à des capteurs) ou dans un cadre plus difficile à estimer lorsque les défaillances ne sont pas detectables -- Ce système d’aide à la décision a été développé à partir des résultats fournis par l’EAFIT, Université partenaire du projet en ColombieÍtem Montaje y evaluación en laboratorio de un sistema prototipo de pico-generación hidroeléctrica con una turbina Michell - Banki(Universidad EAFIT, 2012) Llano Velásquez, Enrique Alberto; Mira Hernández, CarolinaÍtem Study of the effect of the geometrical parameters of the runner and operation conditions on performance and flow characteristics in a cross flow turbine(Universidad EAFIT, 2014) Peláez Restrepo, Juan Diego; París Londoño, Luis SantiagoDue to technological development, massive use of technology, and accelerated population growth in some regions of the planet, the use of renewable energy sources is important to match the increasing electric energy demand -- Hydropower is an important source of renewable energy around the world, due to its simple but efficient way to provide clean electricity generation -- Currently, the cross flow turbine also known as Banki-Turbine has been increasingly used in many places around the world due to its simple structure, modest efficiency and its good performance in small and low head hydroelectric applications -- It is presumed that the massive utilization of this turbines has been limited due to its low efficiency compared to other turbines with efficiencies near to 90% -- Improving this turbine efficiency would make it more attractive and competitive -- This can be achieved by means of studying the turbine operation and determining the most significant parameters in its performance -- Therefore, the interest of this work is to investigate the performance of the cross flow turbine and the flow characteristics through the turbine -- Two kind of analysis are performed in this work -- The objective of the first analysis is to perform experimental tests of some cross flow turbine prototypes under different operating conditions, and determine its performance -- Due to the differences in the geometrical parameters of the runner on every prototype, an extensive work of design, manufacture and assemble was required for the execution of the experiments in order to obtain satisfactory results -- In the second analysis, CFD simulations of the prototypes are performed with the objective of visualizing the flow through the turbine -- Results show that the turbines with the geometrical parameters selected have a poor performance (approx 50%) under the operating conditions tested -- The prototypes with the best performance are those where the nozzle leads the water to a well defined cross flow in the runner, and the water absolute velocity when entering the runner first and second stage corresponds well to the blade angles -- The prototypes tested show a disordered flow pattern through the runner with big recirculation zones and poorly correspondence with the water velocity vectors and the blade angles, which increases losses and leads to lower efficiencies