Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Conceptual research of a multi megawatt downwind turbine
This thesis investigates the advantages and disadvantages of a downwind wind turbine rotor concept compared to an upwind rotor concept. A commercial Suzlon 2.1 MW upwind turbine is used as the baseline and converted into a downwind configuration by moving the rotor downwind from the tower. The effect of the conversion on the loads is investigated. Dynamic stability investigations are made regarding the difference in edgewise damping and a free-yawing downwind option. Finally, new rotors are designed for the upwind and the downwind configuration to evaluate differences in turbine mass and cost. The overall objective of the thesis is to evaluate the possible economic benefits of the downwind configuration compared to the upwind configuration for the chosen example turbine. A comparison of a full design load basis simulated with HAWC2 according to IECstandard shows that the minimum blade tip to tower clearance can be increased by the turbine conversion. The downwind configuration shows a 10% lower extreme flapwise blade root moment due to the coning direction. The tradeoff is a 0.75% lower annual energy production and a 14% higher extreme tower bending moment as moments from the thrust and gravity on the rotor nacelle assembly are aligned. The tower shadow effect increases the blade fatigue loads, and for the edgewise direction a decrease in damping leads to further load increase. Consequently, the difference in edgewise damping of the downwind configuration in comparison to the upwind configuration is studied. This shows that the turbine conversion changes the interaction of the aerodynamic forces, the rotor, and the tower torsional motion. This interaction influences the out-of-plane component of the edgewise modes which is the main contributor to the change in damping. Turbine design parameter such as cone angle and tower torsional stiffness could be used to increase the edgewise damping. Furthermore, a free yawing downwind configuration is investigated as it could reduce the complexity of the yaw system. The ...
Conceptual research of a multi megawatt downwind turbine
This thesis investigates the advantages and disadvantages of a downwind wind turbine rotor concept compared to an upwind rotor concept. A commercial Suzlon 2.1 MW upwind turbine is used as the baseline and converted into a downwind configuration by moving the rotor downwind from the tower. The effect of the conversion on the loads is investigated. Dynamic stability investigations are made regarding the difference in edgewise damping and a free-yawing downwind option. Finally, new rotors are designed for the upwind and the downwind configuration to evaluate differences in turbine mass and cost. The overall objective of the thesis is to evaluate the possible economic benefits of the downwind configuration compared to the upwind configuration for the chosen example turbine. A comparison of a full design load basis simulated with HAWC2 according to IECstandard shows that the minimum blade tip to tower clearance can be increased by the turbine conversion. The downwind configuration shows a 10% lower extreme flapwise blade root moment due to the coning direction. The tradeoff is a 0.75% lower annual energy production and a 14% higher extreme tower bending moment as moments from the thrust and gravity on the rotor nacelle assembly are aligned. The tower shadow effect increases the blade fatigue loads, and for the edgewise direction a decrease in damping leads to further load increase. Consequently, the difference in edgewise damping of the downwind configuration in comparison to the upwind configuration is studied. This shows that the turbine conversion changes the interaction of the aerodynamic forces, the rotor, and the tower torsional motion. This interaction influences the out-of-plane component of the edgewise modes which is the main contributor to the change in damping. Turbine design parameter such as cone angle and tower torsional stiffness could be used to increase the edgewise damping. Furthermore, a free yawing downwind configuration is investigated as it could reduce the complexity of the yaw system. The ...
Conceptual research of a multi megawatt downwind turbine
Wanke, Gesine (Autor:in)
01.01.2019
Wanke , G 2019 , Conceptual research of a multi megawatt downwind turbine . DTU Wind Energy PhD , no. 0094 , DTU Wind Energy . https://doi.org/10.11581/dtu:00000060
Buch
Elektronische Ressource
Englisch
DDC:
690
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