Analysing the Effect of Angle of Attack on Turbulence Intensity, Wake and Power Production for Hexicon Floating Platform
Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
When the wind passes through the wind turbine, it losses a part of its energy and as a result a low momentum region creates behind the wind turbine that refers to the wake. This effect is more significant in a wind farm, where a group of wind turbines are located close to each other in a specific region. Since the wind speed slows down after passing the first row of the turbine, the other rows at the downstream experience lower wind velocity and consequently they can capture less energy in the wind. Wake effect influences the annual power production of a wind farm, not only because of the reduction in the wind velocity but also because of creating turbulence in the flow and generating more vibration loads on the rotors which can reduce the lifetime of the turbines and increase fatigue on the blades. Also when the Angle Of Attack (AOA) changes the shape of the wake varies which influence the annual power production and turbulence intensity of a wind farm.
The main purpose of this work is to investigate the effect of changing the AOA on the annual power production and the turbulence intensity of Hexicon platform. For this aim, different AOA between zero and 15 degrees are considered in the simulations.
ANSYS CFX is applied to model the wind turbine configuration and simulate the fluid flow in different wind direction using unstructured meshing method. In addition wind characteristics profiles such as mean wind velocity, turbulence intensity and length scale at different height are imposed at the inlet of the domain to present the Atmospheric Boundary Layer (ABL). RNG k-ε model is implemented for turbulence modeling. In addition roughness modification is utilized in simulation to get more accurate results in terms of turbulence intensity.
Place, publisher, year, edition, pages
2013. , 90 p.
Horizontal Axis Wind Turbine, Reynolds Number, Thrust Coefficient, Velocity Deficit, Wake Effect, Wind Farm. Turbine Configuration, Turbulence Intensity, Wind Speed
Other Engineering and Technologies not elsewhere specified
IdentifiersURN: urn:nbn:se:kth:diva-129563OAI: oai:DiVA.org:kth-129563DiVA: diva2:653029
2013-09-19, M235, Brinellvägen 68, Stockholm, 14:00 (English)