In recent years, research on environmentally sustainable energy production has endeavoured to exploit new renewable resources, as a consequence of the technological level increase. Particularly, the harvesting of tidal energy has found an emerging interest. The utilization of tidal turbines could be very appealing in numerous sea locations, where local conditions are favourable to energy harvesting, as rip tides at natural or artificial coastal inlets. Nonetheless, often tidal streams may be too slow for achieving an acceptable efficiency of kinetic energy conversion to electricity by means conventional turbine technologies. Indeed, low velocities correspond to low power extraction. Therefore, a device able to augment the flow velocity could be a proper solution to enhance the exploitation of tidal stream energy. The aim of this work is to investigate the possibility of using a barrier, embodying multiple assemblies of turbine plus velocity-augmented device, to enhance the performance of each turbine. An experimental campaign was carried out on a downscaled model of a semi-permeable barrier aiming to mimic this system by means of orifices of equivalent pressure loss. Tests were conducted in a water flume, in subcritical flow conditions at various Froude numbers. Free surface elevation, velocity profiles and pressure drop were measured. The decrease of the free surface level across the barrier model was also studied, as it results in a favourable feature for enhancing the turbine performance. Furthermore, an analytical actuator-disk model was developed for the barrier plus turbine. Finally, a comparison of the model prediction with experimental results is presented in this article.

Experimental investigation of velocity-augmented barriers for tidal stream turbines / Lorenzo Cappietti, Lorenzo Ciappi, Andrea Esposito, Daniele Fiaschi, Giampaolo Manfrida, Bartłomiej Melka, Marcin Nowak, Irene Simonetti, Michal Stebel, Jacek Smolka, Lorenzo Talluri. - ELETTRONICO. - (2019), pp. 1-14. (Intervento presentato al convegno Conference on Substainable Development of Energy, Water and Environment Systerm, SDEWES2019 tenutosi a Dubrovnik, Croatia nel 1-6 Oct. 2019).

Experimental investigation of velocity-augmented barriers for tidal stream turbines

Lorenzo Cappietti;Lorenzo Ciappi;Andrea Esposito;Daniele Fiaschi;Giampaolo Manfrida;MELKA, BARTLOMIEJ;NOWAK, MARCIN;Irene Simonetti;STEBEL, MICHAL;Jacek Smolka;Lorenzo Talluri
2019

Abstract

In recent years, research on environmentally sustainable energy production has endeavoured to exploit new renewable resources, as a consequence of the technological level increase. Particularly, the harvesting of tidal energy has found an emerging interest. The utilization of tidal turbines could be very appealing in numerous sea locations, where local conditions are favourable to energy harvesting, as rip tides at natural or artificial coastal inlets. Nonetheless, often tidal streams may be too slow for achieving an acceptable efficiency of kinetic energy conversion to electricity by means conventional turbine technologies. Indeed, low velocities correspond to low power extraction. Therefore, a device able to augment the flow velocity could be a proper solution to enhance the exploitation of tidal stream energy. The aim of this work is to investigate the possibility of using a barrier, embodying multiple assemblies of turbine plus velocity-augmented device, to enhance the performance of each turbine. An experimental campaign was carried out on a downscaled model of a semi-permeable barrier aiming to mimic this system by means of orifices of equivalent pressure loss. Tests were conducted in a water flume, in subcritical flow conditions at various Froude numbers. Free surface elevation, velocity profiles and pressure drop were measured. The decrease of the free surface level across the barrier model was also studied, as it results in a favourable feature for enhancing the turbine performance. Furthermore, an analytical actuator-disk model was developed for the barrier plus turbine. Finally, a comparison of the model prediction with experimental results is presented in this article.
2019
Proceedings of the 14th Conference on Substainable Development of Energy, Water and Environment Systerm, SDEWES2019
Conference on Substainable Development of Energy, Water and Environment Systerm, SDEWES2019
Dubrovnik, Croatia
1-6 Oct. 2019
Goal 7: Affordable and clean energy
Goal 9: Industry, Innovation, and Infrastructure
Lorenzo Cappietti, Lorenzo Ciappi, Andrea Esposito, Daniele Fiaschi, Giampaolo Manfrida, Bartłomiej Melka, Marcin Nowak, Irene Simonetti, Michal Stebe...espandi
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Utilizza questo identificatore per citare o creare un link a questa risorsa: https://hdl.handle.net/2158/1193329
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