Investigation of Root Spoilers on Horizontal Axis Wind Turbines

Investigation of Root Spoilers on Horizontal Axis Wind Turbines

Kidambi Sekar, A.P.

Ferreira, C.J. (mentor)

Aerospace Engineering

Wind Energy

Aerodynamics and Wind Energy

2016-02-24

For the purpose of flow analysis, the blade of a horizontal axis wind turbine (HAWT) can be divided into the root, mid and the tip regions. The flow in the root region is very complex and is affected due to the rotation of the blade and separation due to the presence of very thick airfoil sections and the higher angle of attacks. Hence, a detailed knowledge of the flow characteristics in the root region is needed to accurately create models that will represent the flow characteristics at the root. There exists an imbalance between the number of studies conducted to analyse the root region of the HAWT blade when compared to the tip region mainly because the contribution of the power production from the tip region of the blade. As the aerodynamic forces in the root regions are not as high as the forces in the tip region, there is a lower contribution to the aerodynamic forces from the root regions. The thesis attempts to simulate the flow in the root sections of the blades by means of simulations and experiments and also look at the effects of spoilers on the root sections of the blade. In order to create a model that can accurately represent the root flow, it was hypothesised that beheading the tip sections of the blade and then scaling it would lead to higher Reynolds numbers in the root span which would resemble closely the actual flow. It was seen that 37.5% of the span could be removed from the tip without any significant effects on the pressure distribution on the inner sections. Other designs such as variable tip shapes were also simulated. The blade was then scaled according to the wind tunnel specifications. The experiment design and the design of the blade was done by using the unsteady three dimensional panel code (UMPM) from TU Delft and the lifting line free vortex code (AWSM) from ECN. A model was then created based on the results of the simulation and the effects of the spoilers on the performance output are tested with wind tunnel experiments at the open jet facility of TU Delft (OJF). A parametric study was carried out to study the influence of spoiler location on the performance. It is seen that the addition of spoilers to the existing blade increases the performance of the wind turbine.

Windenergy
flow control
wind turbine

http://resolver.tudelft.nl/uuid:931f5d12-5b3d-4d1d-ad52-0481f0ff7778

2020-02-24

Student theses

master thesis

(c) 2016 Kidambi Sekar, A.P.