An Experimental Investigation of Wake Characteristics and Power Generation Efficiency of a Small Wind Turbine under Different Tip Speed Ratios
We carried out a wind tunnel experiment to examine the power generation efficiency of a stand-alone miniature wind turbine and its wake characteristics at different tip speed ratios (TSRs) under the same mean inflow velocity. Resistors in the electrical circuit were adjusted to control the TSRs to 0...
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MDPI AG
2020-04-01
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| Online Access: | https://www.mdpi.com/1996-1073/13/8/2113 |
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| author | Yu-Ting Wu Chang-Yu Lin Che-Ming Hsu |
| author_facet | Yu-Ting Wu Chang-Yu Lin Che-Ming Hsu |
| author_sort | Yu-Ting Wu |
| collection | DOAJ |
| description | We carried out a wind tunnel experiment to examine the power generation efficiency of a stand-alone miniature wind turbine and its wake characteristics at different tip speed ratios (TSRs) under the same mean inflow velocity. Resistors in the electrical circuit were adjusted to control the TSRs to 0.9, 1.5, 3.0, 4.1, 5.2, and 5.9. The currents were measured to estimate the turbine power outputs versus the TSRs and then establish the actual power generation coefficient C<sub>p</sub> distribution. To calculate the mechanical power coefficient, a new estimation method of the mechanical torque constant is proposed. A reverse calibration on the blade rotation speed was performed with given electrical voltages and currents that are used to estimate the mechanical power coefficient C<sub>p, mech</sub>. In the experiment, the maximum C<sub>p,mech</sub> was approximately 0.358 (corresponding to the maximum C<sub>p</sub> of 0.212) at the TSR of 4.1. Significant findings indicate that the turbine at the TSR of 5.2 produces a smaller torque but a larger power output compared with that at the TSR of 3.0. This comparison further displays that the turbine at the TSR of 5.2, even with larger power output, still produces a turbine wake that has smaller velocity deficits and smaller turbulence intensity than that at the TSR of 3.0. This behavior demonstrates the significance of the blade-rotation control (i.e., pitch regulation) system to the turbine operation in a large wind farm for raising the overall farm power productivity. |
| first_indexed | 2024-03-10T20:15:49Z |
| format | Article |
| id | doaj.art-ccc2209331c441eea091c648a1c405e7 |
| institution | Directory Open Access Journal |
| issn | 1996-1073 |
| language | English |
| last_indexed | 2024-03-10T20:15:49Z |
| publishDate | 2020-04-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Energies |
| spelling | doaj.art-ccc2209331c441eea091c648a1c405e72023-11-19T22:35:22ZengMDPI AGEnergies1996-10732020-04-01138211310.3390/en13082113An Experimental Investigation of Wake Characteristics and Power Generation Efficiency of a Small Wind Turbine under Different Tip Speed RatiosYu-Ting Wu0Chang-Yu Lin1Che-Ming Hsu2Department of Engineering Science, National Cheng Kung University, Tainan 701, TaiwanDepartment of Engineering Science, National Cheng Kung University, Tainan 701, TaiwanDepartment of Engineering Science, National Cheng Kung University, Tainan 701, TaiwanWe carried out a wind tunnel experiment to examine the power generation efficiency of a stand-alone miniature wind turbine and its wake characteristics at different tip speed ratios (TSRs) under the same mean inflow velocity. Resistors in the electrical circuit were adjusted to control the TSRs to 0.9, 1.5, 3.0, 4.1, 5.2, and 5.9. The currents were measured to estimate the turbine power outputs versus the TSRs and then establish the actual power generation coefficient C<sub>p</sub> distribution. To calculate the mechanical power coefficient, a new estimation method of the mechanical torque constant is proposed. A reverse calibration on the blade rotation speed was performed with given electrical voltages and currents that are used to estimate the mechanical power coefficient C<sub>p, mech</sub>. In the experiment, the maximum C<sub>p,mech</sub> was approximately 0.358 (corresponding to the maximum C<sub>p</sub> of 0.212) at the TSR of 4.1. Significant findings indicate that the turbine at the TSR of 5.2 produces a smaller torque but a larger power output compared with that at the TSR of 3.0. This comparison further displays that the turbine at the TSR of 5.2, even with larger power output, still produces a turbine wake that has smaller velocity deficits and smaller turbulence intensity than that at the TSR of 3.0. This behavior demonstrates the significance of the blade-rotation control (i.e., pitch regulation) system to the turbine operation in a large wind farm for raising the overall farm power productivity.https://www.mdpi.com/1996-1073/13/8/2113Cobra probepower coefficientpower outputtip speed ratiowake measurementwind tunnel experiment |
| spellingShingle | Yu-Ting Wu Chang-Yu Lin Che-Ming Hsu An Experimental Investigation of Wake Characteristics and Power Generation Efficiency of a Small Wind Turbine under Different Tip Speed Ratios Energies Cobra probe power coefficient power output tip speed ratio wake measurement wind tunnel experiment |
| title | An Experimental Investigation of Wake Characteristics and Power Generation Efficiency of a Small Wind Turbine under Different Tip Speed Ratios |
| title_full | An Experimental Investigation of Wake Characteristics and Power Generation Efficiency of a Small Wind Turbine under Different Tip Speed Ratios |
| title_fullStr | An Experimental Investigation of Wake Characteristics and Power Generation Efficiency of a Small Wind Turbine under Different Tip Speed Ratios |
| title_full_unstemmed | An Experimental Investigation of Wake Characteristics and Power Generation Efficiency of a Small Wind Turbine under Different Tip Speed Ratios |
| title_short | An Experimental Investigation of Wake Characteristics and Power Generation Efficiency of a Small Wind Turbine under Different Tip Speed Ratios |
| title_sort | experimental investigation of wake characteristics and power generation efficiency of a small wind turbine under different tip speed ratios |
| topic | Cobra probe power coefficient power output tip speed ratio wake measurement wind tunnel experiment |
| url | https://www.mdpi.com/1996-1073/13/8/2113 |
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