This article presents the characteristic curves of a vertical-axis hydrokinetic tidal turbine of the Darrieus subtype aimed at meeting the electricity demand of port facilities located at harbors and estuaries with low water-speed conditions. The turbine was tested in the water-current flume of the University of Santiago de Compostela for several flow conditions with different water heights and water speeds. Blockage conditions were tested by examining the results from two groups of tests: with and without an accelerator device that restricts the flow around the rotor. The tip speed ratio and the power coefficient were used to characterize the performance of the turbine for each test. Finally, the results for open-field conditions were obtained by applying empirical expressions, which allowed us to assess the performance of the device in estuaries and harbors with known water-flow regimes.

Smart cities have a significant impact on the future of renewable energies as terms such as sustainability and energy saving steadily become more common. In this regard, both wind and hydrokinetic compact-size turbines can play important roles in urban communities by providing energy to nearby consumption points in an environmentally suitable manner. To evaluate the operation of a Darrieus turbine rotor as a wind or hydro microgenerator, a series of wind tunnel and water current flume tests were performed. Power and characteristic curves were obtained for all test conditions. In the wind tests, all curves seemed to be identical, which means that the turbine rotor works properly under open-field conditions. Two blockage correction equations were applied to the water channel tests that were performed under blockage values ranging from 0.2 to 0.35 to estimate the operational behavior in open water. Finally, it has been demonstrated that, with the condition of maintaining the Reynolds number between experiments in the wind tunnel and water flume, the turbine wind characteristics represents the its operation in open-water conditions.

This study investigates the cooling phase in autoclave processing for composite materials, focusing on its impact on thermal properties. A three-dimensional numerical model was developed using Computational Fluid Dynamics (CFD) and validated with experimental data under controlled cooling conditions. The model accurately replicated the thermal dynamics, including heat transfer rates, convection effects and temperature changes along the composite. Numerical results showed that cooling is more uniform in horizontal direction due to material anisotropy. These findings underline the importance of controlling cooling parameters to minimize residual stresses and ensure optimal curing of composites. These findings provide a basis for optimizing autoclave processes in industries requiring high-performance composites.

In this research, the influence of blade geometry on the power stage characterization of cross-flow hydrokinetic turbines and vertical axis under conditions of low current velocity (<1 m/s) has been studied. To carry out the characterization of the power stage, two turbines have been used. The first has three straight blades and corresponds to a SC-Darrieus-type rotor, while the second has three corresponding helical blades with a Gorlov-type rotor. The experimental study has been performed by using a hydrodynamic tunnel and a high precision torque meter with an electric brake, which allows one to obtain the necessary mechanical parameters (torque, rotation speed) for the characterization of the power stage. Analyzing the data obtained from the results of the experimental study, it is determined that, for the same water speed, the Gorlov rotor obtains greater mechanical power than the Darrieus type. In all cases, power coefficient values greater than 1 have been obtained, thus verifying the influence of the blocking phenomenon on the performance of the turbines when they are in confined flow conditions. In turn, the TSR values obtained indicate that these turbines will work mainly by lift since they are higher than unity.

Las turbinas hidrocinéticas se presentan como una alternativa futura para la obtención de energía de las corrientes de agua de manera sostenible. El aumento de eficiencia de dichas turbinas desde distintas aproximaciones constituye una línea de investigación en la que se están concentrado numerosos esfuerzos. Se presenta un estudio experimental donde se analiza la influencia del ángulo de torsión de los álabes en el funcionamiento de las turbinas hidrocinéticas de tipo Darrieus helicoidal. El estudio se realiza en el túnel de agua instalado en la Escuela Politécnica de Mieres (EPM, Universidad de Oviedo) que dispone de la instrumentación necesaria para obtener las características de evolución de la potencia producida con la velocidad de rotación para distintas condiciones de velocidad del flujo y bloqueo de la corriente. Se caracterizaron tres modelos de rotores de turbinas con distintos ángulos de torsión (30°, 45° y 60°), en condiciones de baja velocidad de corriente y bloqueo constante, pudiendo conocer las condiciones de máxima obtención de energía, con diferencias claras entre los casos ensayados. También se compararon los resultados con la potencia máxima que puede recuperarse de una corriente de agua, definida por el modelo del disco actuador para un flujo uniforme en canales, obteniendo máximos valores de eficiencia para el caso de 45° de ángulo de torsión.