The study of 3D effects of struts on a Vertical Axis WindTurbine

Master student:

Fig. 1: H-Shaped vertical axis wind tur-bine. Adapted from ”Noise Emis-sion of a 200 kW Vertical AxisWind Turbine” by E. Mollerstromet al, Journal of Energies 2015.

Willie Lu

Programme:

Flight Performance and Propulsion

Supervisors:

Carlos Simao Ferreira (TU Delft)Delphine de Tavernier (TU Delft)

Summary

To combat climate change and with increased demand of energy, the windenergy sector becomes more important over time. The wind energy pro-ducing systems consists predominantly of horizontal axis wind turbines(HAWT). Beside the HAWTs there are other types of wind turbines, oneof them the vertical axis wind turbines (VAWT) are very promising due toits ability to catch wind from different directions without requiring yawingor pitching systems. This can lead to cheaper wind energy systems andthus a more accessible source of alternative (green) energy. The end goalis to help with the energy transition to fulfill the climate accord.This thesis is about the research on the 3D effects of struts on H-shapedDarrieus vertical axis wind turbines. Vertical axis wind turbines are windturbines where the axis of rotation is perpendicular to the wind direction. Often struts are required to connect theblades to the tower. These structures will have influence on the performance of the turbine. Some effects of strutslike blade-strut interference or blade-wake interactions are often described using correction factors but are not fullyunderstood yet. In this research a 3D numerical study is performed using vortex lattice method CACTUS. TheVAWT and in specific the struts will be modelled with varying design parameters. The effects due to the presenceof strut and its design parameters on the flow field and the performance of the vertical axis wind turbine will bequantified. These models will be compared with data from other methods like the actuator cylinder model. Theknowledge gained here, can be used to first predict the performance influence due to the struts. Secondly it canimprove strut designs for lower drag or even assist the blades with extra torque. Thus increasing the performance ofa vertical axis wind turbine.