Now showing items 1-20 of 33

  • Accurate determination of the frequency response function of submerged and confined structures by using PZT-patches 

    Presas Batlló, Alexandre; Valentín Ruiz, David; Egusquiza Estévez, Eduard; Valero Ferrando, Ma. del Carmen; Egusquiza Montagut, Mònica; Bossio, Matias (2017-03-22)
    Article
    Open Access
    To accurately determine the dynamic response of a structure is of relevant interest in many engineering applications. Particularly, it is of paramount importance to determine the Frequency Response Function (FRF) for ...
  • Advanced condition monitoring of Pelton turbines 

    Egusquiza Montagut, Mònica; Valero Ferrando, Ma. del Carmen; Presas Batlló, Alexandre; Valentín Ruiz, David; Bossio, Matias; Egusquiza Estévez, Eduard (2017)
    Conference report
    Restricted access - publisher's policy
    The ability of hydropower to adapt the electricity generation to the demand is necessary to integrate wind and solar energy to the grid. Nowadays hydropower turbines are required to work under harsher operating conditions ...
  • Advanced condition monitoring of Pelton turbines 

    Egusquiza Montagut, Mònica; Egusquiza Estévez, Eduard; Valero Ferrando, Ma. del Carmen; Presas Batlló, Alexandre; Valentín Ruiz, David; Bossio, Matias (2018-04)
    Article
    Restricted access - publisher's policy
    The ability of hydropower to adapt the electricity generation to the demand is necessary to integrate wind and solar energy into the electrical grid. Nowadays, hydropower turbines are required to work under harsher operating ...
  • A review of pzt patches applications in submerged systems 

    Presas, Alexandre; Luo, Yongyao; Wang, Zhengwei; Valentín Ruiz, David; Egusquiza Montagut, Mònica (Multidisciplinary Digital Publishing Institute (MDPI), 2018-07-12)
    Article
    Open Access
    Submerged systems are found in many engineering, biological, and medicinal applications. For such systems, due to the particular environmental conditions and working medium, the research on the mechanical and structural ...
  • Assessment of the economic and environmental impact of double glazed façade ventilation systems in Mediterranean climates 

    Valentín Ruiz, David; Guardo Zabaleta, Alfredo de Jesús; Egusquiza Estévez, Eduard; Valero Ferrando, Ma. del Carmen; Alavedra, Pere (2013-09-30)
    Article
    Open Access
    Free convection is the most often used method in order to reduce solar load gains on a building with double glazed façades (DGFs). However, depending on the climate factors, the thermal performance of a DGF may not be ...
  • Condition monitoring of a prototype turbine. Description of the system and main results 

    Valero Ferrando, Ma. del Carmen; Egusquiza Estévez, Eduard; Presas Batlló, Alexandre; Valentín Ruiz, David; Egusquiza Montagut, Mònica; Bossio, Matias (Institute of Physics (IOP), 2017)
    Conference report
    Open Access
    The fast change in new renewable energy is affecting directly the required operating range of hydropower plants. According to the present demand of electricity, it is necessary to generate different levels of power. Because ...
  • Condition monitoring of pump-turbines. New challenges 

    Egusquiza Estévez, Eduard; Valero Ferrando, Ma. del Carmen; Valentín Ruiz, David; Presas Batlló, Alexandre; Rodriguez Godoy, Cristian (2015-05)
    Article
    Open Access
    At present, pumped storage is the only system to store huge amounts of energy. The surplus of energy in the electrical grid is used for pumping water from a lower to a higher reservoir (pump operation). At peak hours or ...
  • Detection and analysis of part load and full load instabilities in a real Francis turbine prototype 

    Presas Batlló, Alexandre; Valentín Ruiz, David; Egusquiza Estévez, Eduard; Valero Ferrando, Ma. del Carmen (Institute of Physics (IOP), 2017)
    Conference report
    Open Access
    Francis turbines operate in many cases out of its best effici ency point, in order to regulate their output power according to the instantaneous ener gy demand of the grid. Therefore, it is of paramount importance to analyse ...
  • 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
    Restricted access - publisher's policy
    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 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)
    Conference report
    Open Access
    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)
    Conference report
    Open Access
    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
    Open Access
    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 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
    Restricted access - publisher's policy
    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
    Restricted access - publisher's policy
    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 ...
  • 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
    Open Access
    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 Pelton turbine runner 

    Egusquiza Montagut, Mònica; Egusquiza Estévez, Eduard; Valentín Ruiz, David; Valero Ferrando, Ma. del Carmen; Presas Batlló, Alexandre (Elsevier, 2017-11)
    Article
    Restricted access - publisher's policy
    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 ...
  • 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
    Open Access
    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
    Restricted access - publisher's policy
    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 ...
  • Influence of non-rigid surfaces on the dynamic response of a submerged and confined disk 

    Valentín Ruiz, David; Presas Batlló, Alexandre; Egusquiza Estévez, Eduard; Valero Ferrando, Ma. del Carmen (2015)
    Conference report
    Open Access
    Determining the dynamic response of submerged and confined disk-like structures is of interest in the hydraulic turbines field. Disks present similar dynamic characteristics than hydraulic turbine runners, especially in ...
  • Influence of the added mass effect and boundary conditions on the dynamic response of submerged and confined structures 

    Valentín Ruiz, David; Presas Batlló, Alexandre; Egusquiza Estévez, Eduard; Valero Ferrando, Ma. del Carmen (2014)
    Conference report
    Open Access
    The dynamic response of submerged and confined disk-like structures is of interest in the flied of hydraulic machinery, especially in hydraulic turbine runners. This response is difficult to be estimated with accuracy due ...