Hydropower plays a key role in the actual energy market due to its fast response and regulation capacity. In that way, hydraulic turbines are increasingly demanded work at off-design conditions, where complex flow patterns cavitation appear, especially Francis turbines. The draft tube surge is phenomenon appears below above Best Efficiency Point (BEP). It low frequency consisting of vortex rope runner outlet tube, which can become unstable when coincides with natural circuit. At this...

To accurately determine the dynamic response of a structure is relevant interest in many engineering applications. Particularly, it paramount importance to Frequency Response Function (FRF) for structures subjected loads order avoid resonance and fatigue problems that can drastically reduce their useful life. One challenging case experimental determination FRF submerged confined structures, such as hydraulic turbines, which are greatly affected by reported cases past. The utilization...

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 stops. In this situation, dynamic loads stresses over structure are high, registering some failures time, especially runner. Therefore, it is important know runner while operation, i.e., natural frequencies, damping mode shapes, order avoid resonance fatigue problems. Detecting frequencies...

Due to the increasing share of new renewable energies like wind and solar in generation electricity need for power regulation energy storage is becoming paramount importance. One systems store huge amounts pumped using reversible hydropower units. The machines used these plants are pump-turbines, which can operate as a pump turbine. surplus electrical during low consumption hours be converted into potential hydraulic by pumping water higher level. stored again operating runner requirements...

One of the main causes damage in hydraulic turbines is cavitation. While not all cavitation appearing a turbine destructive type, erosive can severely affect structure, thus increasing maintenance costs and reducing remaining useful life machine. Of types cavitation, maximum erosion occurs when clouds bubbles collapse on runner surface (cloud cavitation). When this it associated with substantial increase noise, vibrations that are propagated everywhere throughout The generation these may...

Determining the dynamic response of submerged and confined disklike structures is interest in engineering applications, such as hydraulic turbine runners. This heavily affected by added mass damping well proximity solid boundaries. These boundaries are normally considered completely rigid theoretical or numerical calculations, however, this assumption not always valid. Some turbines have noncompletely stiff casings, which can modify runner itself, affecting specially its natural frequencies...

Nowadays, hydropower is demanded to provide flexibility and fast response into the electrical grid in order compensate non-constant electricity generation of other renewable sources. Hydraulic turbines are therefore work under off-design conditions more frequently, where different complex hydraulic phenomena appear, affecting machine stability as well reducing useful life its components. Hence, it desirable detect real-time these assess operation machine. In this paper, a large medium-head...

Determining the natural frequencies and mode shapes of rotating turbomachinery components from both stationary reference frames is paramount importance to avoid resonance problems that could affect normal operation machine, or even cause critical damages in these components. Due their similarity real engineering cases, this topic has been experimentally analyzed past for disk-shaft assemblies rotor disk-blades (bladed-disk blisk). The same less disk-blades-disk assemblies, although such...

A Kaplan turbine unit from a new powerplant experienced high levels of vibrations and noise during the acceleration to nominal speed. These remained very at speed no load. first analysis seemed indicate possible blade resonance phenomenon as highest were measured on head cover. Nevertheless, after some modifications root blades, commissioning was delayed several months. To determine origin these vibrations, an array sensors installed in machine. Different types tests performed. Experimental...

The fast change in new renewable energy is affecting directly the required operating range of hydropower plants. According to present demand electricity, it necessary generate different levels power. Because its ease regulate and huge storage capacity energy, unique source that can adapt demand.

Hydropower plants are of paramount importance for the integration intermittent renewable energy sources in power grid. In order to match generated and consumed, Large hydraulic turbines have work under off-design conditions, which may lead dangerous unstable operating points involving hydraulic, mechanical electrical system. Under these stability grid safety plant itself can be compromised. For many Francis Turbines one critical points, that usually limits maximum output power, is full load...

Crack appearance in the blade is most common type of fatigue damage Francis turbines. However, it sometimes difficult to detect cracks time using current monitoring system, even when they are very large. To better monitor cracks, imperative research effect a crack on dynamic behavior turbine. In this paper, turbine runner model with has been researched numerically. The intact numerical was first validated by experimental data available. Then, created at intersection line between one and...

The global trend on energy integration and building efficiency is making both researchers developers look for technical solutions to use facade surfaces harvesting. In this work, the assessment of thermal performance a double-skin (DSF) with venetian blind-type structure used as solar collector by means computational fluid dynamics (CFD) presented. A Venetian blind would allow heat rejection/energy harvesting exterior views simultaneously can be easily integrated into DSF aesthetical design....

In the coming decades, proportion of wind–solar energy in power system significantly increases, resulting to uncertainties fluctuation abundant regions. The flexibility operation Pumped Storage Power Plants (PSPPs) has already been widely recognized regulate fluctuations; however, less is known about regulation reliability PSPP affected by them. It a challenge, since various exist during this process. Here, mathematical model with solar–wind–hydro hybrid generation adopted investigate PSPP....

Accurate determination of modal parameters for disk-like structures submerged in heavy fluids is a topic interest many fields. For instance, some type hydraulic turbomachinery can be modelled as disk due to the similarity their mode shapes. Although recent years studies have analyzed and correctly predicted fluid added mass effect on natural frequencies shapes these types structures, it particularly challenging determine damping characterize its most influential effects. In this article,...