کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
300720 | 512488 | 2013 | 9 صفحه PDF | دانلود رایگان |
This article describes a new method for simulating unsteady hydrodynamics forces and moments on the blades of a crossflow ‘Darrieus’ turbine with active pitch variation. This method is based on the ONERA-EDLIN dynamic stall model, coupled with a momentum streamtube model to take into account the turbine interference on the flow. Both models are presented, and compared separately with experimental results for a pitching airfoil for the ONERA-EDLIN model; and for Darrieus turbine for the momentum theory. The model coupling is then detailed and compared with experimental data taken from the open literature [1] The turbine has 2 straight blades with a NACA 0012 section operating in water at a mean chord Reynolds number of 4 × 104 for tip speed ratio λ = 2.5, 5 and 7.5. Good agreement was found for average λ = 5, and qualitative agreement could be obtained at low and high λ, where dynamic stall effects and interference effects respectively are predominant. This is positive because λ = 5 is the closest value from the optimal power production point. Variable pitch is finally introduced in the model and several functions are tested in order to increase efficiency. A maximum increase of 53% on the power coefficient was found to occur with a sinusoidal law.
► Hybrid model for unsteady force and performance prediction on a crossflow Darrieus turbine.
► Based on the ONERA-EDLIN dynamic stall model, and a momentum « streamtube theory ».
► Pitch variation which results in power increase at very low or zero extra energy cost.
Journal: Renewable Energy - Volume 52, April 2013, Pages 209–217