| 1. |
- Dyachuk, Eduard, et al.
(författare)
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Measurements of the Aerodynamic Normal Forces on a 12-kW Straight-Bladed Vertical Axis Wind Turbine
- 2015
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Ingår i: Energies. - : MDPI AG. - 1996-1073. ; 8:8
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Tidskriftsartikel (refereegranskat)abstract
- The knowledge of unsteady forces is necessary when designing vertical axis wind turbines (VAWTs). Measurement data for turbines operating at an open site are still very limited. The data obtained from wind tunnels or towing tanks can be used, but have limited applicability when designing large-scale VAWTs. This study presents experimental data on the normal forces of a 12-kW straight-bladed VAWT operated at an open site north of Uppsala, Sweden. The normal forces are measured with four single-axis load cells. The data are obtained for a wide range of tip speed ratios: from 1.7 to 4.6. The behavior of the normal forces is analyzed. The presented data can be used in validations of aerodynamic models and the mechanical design for VAWTs.
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| 2. |
- Dyachuk, Eduard, et al.
(författare)
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Numerical Validation of a Vortex Model Against Experimental Data on a Straight-Bladed Vertical Axis Wind Turbine
- 2015
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Ingår i: Energies. - Basel : MDPI. - 1996-1073. ; 8:10, s. 11800-11820
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Tidskriftsartikel (refereegranskat)abstract
- Cyclic blade motion during operation of vertical axis wind turbines (VAWTs) imposes challenges on the simulations models of the aerodynamics of VAWTs. A two-dimensional vortex model is validated against the new experimental data on a 12-kW straight-bladed VAWT, which is operated at an open site. The results on the normal force on one blade are analyzed. The model is assessed against the measured data in the wide range of tip speed ratios: from 1.8 to 4.6. The predicted results within one revolution have a similar shape and magnitude as the measured data, though the model does not reproduce every detail of the experimental data. The present model can be used when dimensioning the turbine for maximum loads.
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| 3. |
- Dyachuk, Eduard, et al.
(författare)
-
Simulating Dynamic Stall Effects for Vertical Axis Wind Turbines Applying a Double Multiple Streamtube Model
- 2015
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Ingår i: Energies. - : MDPI AG. - 1996-1073. ; 8:2, s. 1353-1372
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Tidskriftsartikel (refereegranskat)abstract
- The complex unsteady aerodynamics of vertical axis wind turbines (VAWT) poses significant challenges to the simulation tools. Dynamic stall is one of the phenomena associated with the unsteady conditions for VAWTs, and it is in the focus of the study. Two dynamic stall models are compared: the widely-used Gormont model and a Leishman-Beddoes-type model. The models are included in a double multiple streamtube model. The effects of flow curvature and flow expansion are also considered. The model results are assessed against the measured data on a Darrieus turbine with curved blades. To study the dynamic stall effects, the comparison of force coefficients between the simulations and experiments is done at low tip speed ratios. Simulations show that the Leishman-Beddoes model outperforms the Gormont model for all tested conditions.
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| 4. |
- Rossander, Morgan, et al.
(författare)
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Evaluation of a Blade Force Measurement System for a Vertical Axis Wind Turbine Using Load Cells
- 2015
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Ingår i: Energies. - : MDPI AG. - 1996-1073. ; 8:6, s. 5973-5996
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Tidskriftsartikel (refereegranskat)abstract
- Unique blade force measurements on an open site straight-bladed vertical axis wind turbine have been performed. This paper presents a method for measuring the tangential and normal forces on a 12-kW vertical axis wind turbine prototype with a three-bladed H-rotor. Four single-axis load cells were installed in-between the hub and the support arms on one of the blades. The experimental setup, the measurement principle, together with the necessary control and measurement system are described. The maximum errors of the forces and accompanying weather data that can be obtained with the system are carefully estimated. Measured forces from the four load cells are presented, as well as the normal and tangential forces derived from them and a comparison with theoretical data. The measured torque and bending moment are also provided. The influence of the load cells on the turbine dynamics has also been evaluated. For the aerodynamic normal force, the system provides periodic data in agreement with simulations. Unexpected mechanical oscillations are present in the tangential force, introduced by the turbine dynamics. The measurement errors are of an acceptable size and often depend on the measured variable. Equations are presented for the calculation of measurement errors.
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