Comparison between symmetrical and cambered blade sections for small-scale wind turbines with low center of gravity
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- HARA Yutaka
- Graduate School of Engineering, Tottori University
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- SUMI Takahiro
- Graduate School of Engineering, Tottori University
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- WAKIMOTO Mutsuko
- Graduate School of Engineering, Tottori University
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- KOGO Shohei
- Graduate School of Engineering, Tottori University
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- MIZUGUCHI Sho
- Graduate School of Engineering, Tottori University
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- YOSHIMI Kouichi
- Graduate School of Engineering, Tottori University
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- AKIMOTO Hiromichi
- Division of Ocean Systems Engineering, KAIST
抄録
Low-center-of-gravity wind turbines (LCGWTs) characterized by tapered blades whose chord length c increases nonlinearly from the top (where c = 0.11 m) to the bottom (where c = 0.17 m) of each blade. Further, turbines featuring these blades do not need any arms, or even a center pole in the rotor. Two experimental LCGWTs (diameter: 0.4 m; height: 0.25 m) with symmetrical blades (NACA 0018) and cambered blades were built. A dead band, which is a band of tip speed ratio (TSR) where the rotor has negative torque at TSR lower than that where the maximum power-coefficient condition is achieved, was observed when symmetrical blades were subjected to low wind speed. In contrast, no dead band was observed for the cambered blades. Under high wind speeds and over a wide range of TSR values, performance of the LCGWTs was better with cambered blades than with symmetrical blades. Computational fluid dynamics (CFD) analysis of 2-dimensional rotors whose blade sections corresponded to the blade sections at the equatorial planes of both types of LCGWTs showed the same tendency. Performance predictions by the blade element momentum (BEM) method using aerodynamic data on the NACA 0018 blades showed some agreement with the CFD analysis. For the cambered blade rotor, Wilson and Walker's empirical correction of the thrust coefficient, a correction that is typically used in simulations of horizontal axis wind turbines, brought the BEM prediction closer to the CFD prediction than Glauert's correction did. However, the agreement between the BEM prediction with Wilson and Walker's correction and the CFD prediction of the cambered blade rotor was thought to be just a coincidence due to large difference on the torque variations between BEM and CFD. At least, the Wilson and Walker's correction predicts larger torque than the Glauert's correction at high TSR region.
収録刊行物
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- Journal of Fluid Science and Technology
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Journal of Fluid Science and Technology 9 (1), JFST0006-JFST0006, 2014
一般社団法人 日本機械学会
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詳細情報 詳細情報について
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- CRID
- 1390282680223047680
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- NII論文ID
- 130003393095
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- ISSN
- 18805558
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- 本文言語コード
- en
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- データソース種別
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- JaLC
- Crossref
- CiNii Articles
- KAKEN
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- 抄録ライセンスフラグ
- 使用不可