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Ara es mostren els items 21-40 de 73

    • Dynamic behaviour of a Francis turbine during voltage regulation in the electrical power system 

      Vagnoni, Elena; Valentín Ruiz, David; Avellan, François (2021-02-01)
      Article
      Accés obert
      Hydroelectric units can be operated in synchronous condenser mode to provide reactive power to the electrical power system (EPS) for voltage regulation. In this operating mode, the hydraulic turbine consumes active power ...

    • Dynamic response of a rotating disk submerged and confined. Influence of the axial gap 

      Presas Batlló, Alexandre; Valentín Ruiz, David; Egusquiza Estévez, Eduard; Valero Ferrando, Ma. del Carmen; Seidel, Ulrich (2016-04-01)
      Article
      Accés obert
      In this paper, the natural frequencies and mode shapes of a rotating disk submerged and totally confined inside a rigid casing, have been obtained. These have been calculated analytically, numerically and experimentally ...

    • Dynamic response of Pelton runners: Numerical and experimental analysis in prototypes 

      Egusquiza Montagut, Mònica; Valentín Ruiz, David; Presas Batlló, Alexandre; Egusquiza Estévez, Eduard (Elsevier, 2020-09-01)
      Article
      Accés obert
      Worldwide electricity generation is featured by the growth of intermittent renewable energies. In this context, hydropower plays a fundamental role because it provides flexibility to the power grid and ensures its stability. ...

    • Dynamic response of the MICA runner. Experiment and simulation 

      Valentín Ruiz, David; Presas Batlló, Alexandre; Egusquiza Estévez, Eduard; Valero Ferrando, Ma. del Carmen; Bossio, Matias (Institute of Physics (IOP), 2017)
      Text en actes de congrés
      Accés obert
      Studying the dynamic response of Francis turbine runners is of paramount importance in order to avoid resonance problems during operating conditions. For this purpose, the natural frequencies as well as their associated ...

    • Experimental analysis of the dynamic behavior of a rotating disk submerged in water 

      Presas Batlló, Alexandre; Valentín Ruiz, David; Egusquiza Estévez, Eduard; Valero Ferrando, Ma. del Carmen; Seidel, Ulrich (2014)
      Text en actes de congrés
      Accés obert
      To study the dynamic behavior of turbine runners (natural frequencies and mode shapes) not only the added mass effect of still water has to be considered. Also the effect of rotation may not be neglected in the dynamic ...

    • Experimental and Numerical Design and Evaluation of a Vibration Bioreactor using Piezoelectric Patches 

      Valentín Ruiz, David; Roehr, Charline; Presas Batlló, Alexandre; Heiss, Christian; Egusquiza Estévez, Eduard; Bosbach, Wolfram A. (Multidisciplinary Digital Publishing Institute (MDPI), 2019-01-21)
      Article
      Accés obert
      n this present study, we propose a method for exposing biological cells to mechanical vibration. The motive for our research was to design a bioreactor prototype in which in-depth in vitro studies about the influence of ...

    • Experimental and numerical investigation on the influence of a large crack on the modal behaviour of a Kaplan turbine blade 

      Zhang, Ming; Valentín Ruiz, David; Valero Ferrando, Ma. del Carmen; Presas Batlló, Alexandre; Egusquiza Montagut, Mònica; Egusquiza Estévez, Eduard (Elsevier, 2020-01-01)
      Article
      Accés obert
      A large crack was discovered on one blade of a Kaplan turbine prototype after the inspection of the machine. In order to know the origin of the crack, a failure analysis was previously carried out (Zhang et al., 2019). To ...

    • Experimental investigation on the dynamic response of Pelton runners 

      Egusquiza Montagut, Mònica; Valero Ferrando, Ma. del Carmen; Presas Batlló, Alexandre; Valentín Ruiz, David; Egusquiza Estévez, Eduard (Institute of Physics (IOP), 2019)
      Text en actes de congrés
      Accés obert
      An effective condition monitoring is essential to increase the availability of Pelton turbines and to avoid unexpected damage. The main challenge consists in determining the deformations and the stresses in the runner while ...

    • Experimental measurements of the natural frequencies and mode shapes of rotating disk-blades-disk assemblies from the stationary frame 

      Presas Batlló, Alexandre; Valentín Ruiz, David; Valero Ferrando, Ma. del Carmen; Egusquiza Montagut, Mònica; Egusquiza Estévez, Eduard (Multidisciplinary Digital Publishing Institute, 2019-09-14)
      Article
      Accés obert
      Determining the natural frequencies and mode shapes of rotating turbomachinery components from both rotating and stationary reference frames is of paramount importance to avoid resonance problems that could affect the ...

    • Experimental study of a vibrating disk submerged in a fluid-filled tank and confined with a nonrigid cover 

      Valentín Ruiz, David; Presas Batlló, Alexandre; Egusquiza Estévez, Eduard; Valero Ferrando, Ma. del Carmen; Egusquiza Montagut, Mònica (2017-04-01)
      Article
      Accés restringit per política de l'editorial
      Determining the dynamic response of submerged and confined disklike structures is of interest in engineering applications, such as in hydraulic turbine runners. This dynamic response is heavily affected by the added mass ...

    • Experimental study on the added mass and damping of a disk submerged in a partially fluid-filled tank with small radial confinement 

      Valentín Ruiz, David; Presas Batlló, Alexandre; Egusquiza Estévez, Eduard; Valero Ferrando, Ma. del Carmen (2014-07-16)
      Article
      Accés restringit per política de l'editorial
      The dynamic response of submerged and confined disk-like structures is of interest in engineering applications, such as in hydraulic turbine runners. This response is difficult to be estimated with accuracy due to the ...

    • Experimental study on the influence of vibration amplitude on the fluid damping of a submerged disk 

      Moraga González, Greco Alonso; Xia, Xiang; Roig López, Sergi; Valero Ferrando, Ma. del Carmen; Valentín Ruiz, David; Egusquiza Montagut, Mònica; Zhou, Lingjiu; Egusquiza Estévez, Eduard; Presas Batlló, Alexandre (Elsevier, 2023-10)
      Article
      Accés obert
      Accurate determination of modal parameters for disk-like structures submerged in heavy fluids is a topic of interest in many fields. For instance, some type of hydraulic turbomachinery can be modelled as disk structures ...

    • Extension of operating range in pump-turbines. Influence of head and load 

      Valero Ferrando, Ma. del Carmen; Egusquiza Montagut, Mònica; Egusquiza Estévez, Eduard; Presas Batlló, Alexandre; Valentín Ruiz, David; Bossio, Matias (2017-12-19)
      Article
      Accés obert
      Due to the increasing share of new renewable energies like wind and solar in the generation of electricity the need for power regulation and energy storage is becoming of paramount importance. One of the systems to store ...

    • Failure investigation of a Kaplan turbine blade 

      Zhang, Ming; Valentín Ruiz, David; Valero Ferrando, Ma. del Carmen; Egusquiza Montagut, Mònica; Egusquiza Estévez, Eduard (Elsevier, 2019-03-01)
      Article
      Accés obert
      In this paper, an uncommon failure of a Kaplan turbine blade has been analyzed. After the monitoring system detected a sudden increase in vibration levels, the turbine was inspected. The inspection showed that a large crack ...

    • Failure investigation of a Pelton turbine runner 

      Egusquiza Montagut, Mònica; Egusquiza Estévez, Eduard; Valentín Ruiz, David; Valero Ferrando, Ma. del Carmen; Presas Batlló, Alexandre (Elsevier, 2017-11)
      Article
      Accés obert
      In this paper, an uncommon failure of a Pelton turbine has been analyzed. After the monitoring system detected a sudden increase in the vibration levels, the turbine was inspected. The inspection showed that a fragment of ...

    • Failure investigation of a solar tracker due to wind-induced torsional galloping 

      Valentín Ruiz, David; Valero Ferrando, Ma. del Carmen; Egusquiza Montagut, Mònica; Presas Batlló, Alexandre (Elsevier, 2022-05-01)
      Article
      Accés obert
      Solar power installations are increasing every year due to the decarbonization policy established around the world. Photovoltaic (PV) systems and specifically one-axis solar trackers are the most used type of installations ...

    • Feasibility of detecting natural frequencies of hydraulic turbines while in operation, using strain gauges 

      Valentín Ruiz, David; Presas Batlló, Alexandre; Bossio, Matias; Egusquiza Montagut, Mònica; Egusquiza Estévez, Eduard; Valero Ferrando, Ma. del Carmen (Multidisciplinary Digital Publishing Institute (MDPI), 2018-01-10)
      Article
      Accés obert
      Nowadays, hydropower plays an essential role in the energy market. Due to their fast response and regulation capacity, hydraulic turbines operate at off-design conditions with a high number of starts and stops. In this ...

    • Feasibility of Using PZT Actuators to Study the Dynamic Behavior of a Rotating Disk due to Rotor-Stator Interaction 

      Presas Batlló, Alexandre; Egusquiza Estévez, Eduard; Valero Ferrando, Ma. del Carmen; Valentín Ruiz, David; Seidel, Ulrich (2014-07-01)
      Article
      Accés restringit per política de l'editorial
      In this paper, PZT actuators are used to study the dynamic behavior of a rotating disk structure due to rotor-stator interaction excitation. The disk is studied with two different surrounding fluids-air and water. The study ...

    • Hybridization in Kaplan turbines. Wear and tear assessment 

      Valentín Ruiz, David; Presas Batlló, Alexandre; Egusquiza Montagut, Mònica; Valero Ferrando, Ma. del Carmen (IOP Publishing, 2022)
      Text en actes de congrés
      Accés obert
      In the current energy market, hydraulic turbines are increasingly demanded to work in Frequency containment reserve (FCR) mode to compensate the constant frequency fluctuations in the electrical grid. To do so, hydraulic ...

    • Hybridization of a RoR HPP with a BESS—The XFLEX HYDRO Vogelgrun Demonstrator 

      Kadam, Serdar; Hofbauer, Wolfgang; Lais, Stefan; Neuhauser, Magdalena; Wurm, Erich; Fernandes Lameiro, Luisa; Bourien, Yves Marie; Païs, Grégory; Drommi, Jean-Louis; Nicolet, Christophe; Landry, Christian; Dreyer, Matthieu; Valero Ferrando, Ma. del Carmen; Presas Batlló, Alexandre; Valentín Ruiz, David (2023-07-01)
      Article
      Accés obert
      In the XFLEX HYDRO Vogelgrun demonstrator, a run-of-river hydropower plant, the hybridization of one turbine-generator unit with a battery energy storage system is being investigated. This paper describes the integration ...