In this master thesis the response of a hexagonal 5D staggered layout wind farm, composed by seven IEA 15-MW Floating Offshore Wind Turbines, with the environmental conditions of a North-Sea site, has been evaluated. Three different turbulent wind inflows have been applied to the plant: two are characterized by a Kaimal spectrum, with coherence in all the three wind components and just in the horizontal component, respectively, and the remaining one is a Mann turbulent wind. The software FAST.Farm has been the tool to simulate the farm operation, while the turbulent wind time-series data have been generated with TurbSim, for the Kaimal cases, and Mann Turbulence Generator, for the Mann one. The first step has been to test the methodology on a farm with two 8D distanced aligned turbines, to then apply it to the plant configuration under analysis. Lastly, a comparison between the floating farm and a monopile farm, with the same layout and environmental conditions, has been set up. As a result, the floating configuration under study has been evidenced to be good from all the analyzed points of view; in particular, just two of the seven rotors operate in waked conditions and the layout ensures acceptable plant performance and relatively contained platform motions and reasonable axial stresses and short-terms fatigue damages for all the turbines and inflows. Using instead bottom-fixed turbines would be better, in terms of quantity and quality of extractable power, but unfeasible with these environmental conditions; the water depth characterizing the site (200m) does not permit the installation of this type of technology. The comparison, in fact, has not been made to be end in itself, but it has permitted to find out and confirm some of the conclusions concerning the floating case. The real contributions of this master thesis, anyway, have been those of increasing the robustness of the FAST.Farm use and developing models for the future studies of Politecnico di Milano’s Galleria del Vento. The latters are, in fact, focusing on the offshore floating wind energy, contributing to the spread of this promising technology, and so to the decarbonisation.
In questa tesi magistrale viene analizzato il responso di un parco eolico esagonale di sette IEA 15-MW Floating Offshore Wind Turbines sfalsate di 5D, con le condizioni ambientali di un sito nel Mare del Nord. L’impianto è stato sottoposto a tre tipologie di flussi ventosi turbolenti differenti: due caratterizzati da uno spettro di Kaimal, rispettivamente con coerenza in tutte e tre le componenti del vento e solo nella componente orizzontale, e il rimanente consiste in una turbolenza di Mann. Lo strumento utilizzato per simulare il funzionamento della centrale è stato FAST.Farm, mentre i dati delle serie temporali del vento turbolento sono stati generati con TurbSim, per i casi di Kaimal, e Mann Turbulence Generator, per quello di Mann. Il punto di partenza è stato testare la metodologia su un impianto di due turbine allineate distanziate di 8D, per poi applicarlo alla configurazione oggetto dello studio. Infine è stato condotto un paragone tra il parco galleggiante e uno con fondazioni monopile, con la stesso assetto e stesse condizioni ambientali. Come risultato, la configurazione galleggiante studiata è risultata essere buona da tutti i punti di vista analizzati; in particolare, solo due dei sette aereogeneratori subiscono le scie degli altri e la disposizione garantisce prestazioni accettabili e movimenti della piattaforma relativamente contenuti e ragionevoli sforzi assiali e danni a fatica a breve termine ragionevoli per tutte le turbine e i flussi considerati. Utilizzare turbine monopile sarebbe meglio in termini di quantità e qualità della potenza estraibile, ma infattibile con queste condizioni ambientali; la profondità dell’acqua del sito (200m) non permette l’installazione di questo tipo di tecnologia. Il paragone, infatti, non è stato fatto per essere fine a se stesso, ma ha permesso di trovare e confermare alcune delle conclusioni riguardanti il caso galleggiante. Il vero contributo di questa tesi magistrale, tuttavia, è stato quello di rafforzare l’utilizzo di FAST.Farm e sviluppare modelli per i futuri studi della Galleria del Vento del Politecnico di Milano. Questi sono infatti focalizzati sull’energia eolica offshore galleggiante, contribuendo alla diffusione di questa tecnologia promettente e, quindi, alla decarbonizzazione.
Response analysis of a seven-turbines floating offshore wind farm in the North Sea with different turbulent inflows
Scaparrotti, Alessio
2021/2022
Abstract
In this master thesis the response of a hexagonal 5D staggered layout wind farm, composed by seven IEA 15-MW Floating Offshore Wind Turbines, with the environmental conditions of a North-Sea site, has been evaluated. Three different turbulent wind inflows have been applied to the plant: two are characterized by a Kaimal spectrum, with coherence in all the three wind components and just in the horizontal component, respectively, and the remaining one is a Mann turbulent wind. The software FAST.Farm has been the tool to simulate the farm operation, while the turbulent wind time-series data have been generated with TurbSim, for the Kaimal cases, and Mann Turbulence Generator, for the Mann one. The first step has been to test the methodology on a farm with two 8D distanced aligned turbines, to then apply it to the plant configuration under analysis. Lastly, a comparison between the floating farm and a monopile farm, with the same layout and environmental conditions, has been set up. As a result, the floating configuration under study has been evidenced to be good from all the analyzed points of view; in particular, just two of the seven rotors operate in waked conditions and the layout ensures acceptable plant performance and relatively contained platform motions and reasonable axial stresses and short-terms fatigue damages for all the turbines and inflows. Using instead bottom-fixed turbines would be better, in terms of quantity and quality of extractable power, but unfeasible with these environmental conditions; the water depth characterizing the site (200m) does not permit the installation of this type of technology. The comparison, in fact, has not been made to be end in itself, but it has permitted to find out and confirm some of the conclusions concerning the floating case. The real contributions of this master thesis, anyway, have been those of increasing the robustness of the FAST.Farm use and developing models for the future studies of Politecnico di Milano’s Galleria del Vento. The latters are, in fact, focusing on the offshore floating wind energy, contributing to the spread of this promising technology, and so to the decarbonisation.| File | Dimensione | Formato | |
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https://hdl.handle.net/10589/208970