PIV Measurement of Flow Field of the Wind Turbine with a Brimmed Diffuser

Toshimitsu, Kazuhiko; Nishikawa, Koutarou; Ohya, Yuji

doi:10.1299/kikaib.72.1236

Cited by 2 publications

(1 citation statement)

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“…Since upstream mean velocity is 7.0m/s, the inlet mean velocity is 2.6m/s larger than upstream one. The flow acceleration is induced by the low pressure region which is caused by the unsteady vortices behind the flange [1,3]. The wind power P with the diffuser is about 2.6 times as large as that without the diffuser.…”

Section: Downstream Flow Of the Diffusermentioning

confidence: 99%

PIV measurements of flows around the wind turbines with a flanged-diffuser shroud

Toshimitsu

Nishikawa²,

Haruki

et al. 2008

J. Therm. Sci.

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The wind turbines with a flanged-diffuser shroud -so called "wind lens turbine"-are developed as one of high performance wind turbines by Ohya et al. In order to investigate the flow characteristics and flow acceleration, the paper presents the flow velocity measurements of a long-type and a compact-type wind turbines with a flanged-diffuser shroud by particle image velocimetry. In the case of the long type wind turbine, the velocity vectors of the inner flow field of the diffuser for turbine blades rotating and no blades rotating are presented at Reynolds number, 0.9×105. Furthermore the flow fields between with and without rotating are compared. Through the PIV measurement results, one can realize that the turbine blades rotating affects as suppress the disturbance and the flow separation near the inner wall of the diffuser. The time average velocity vectors are made on the average of the instantaneous velocity data. There are two large vortices in downstream region of the diffuser. One vortex behind the flange acts as suck in wind to the diffuser and raise the inlet flow velocity. Another large vortex appears in downstream. It might be act as blockage vortex of main flow. The large blockage vortex is not clear in the instantaneous velocity vectors, however it exists clearly in the time average flow field. The flow field around the wind turbine with a compact-type flanged-diffuser shroud is also investigated. The flow pattern behind the flange of the compact-type turbine is the same as the long-type one. It means that the effect of flow acceleration is caused by the unsteady vortices behind the flange. The comparison with CFD and PIV results of meridional time-average streamlines after the compact-type diffuser is also presented.

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Section: Downstream Flow Of the Diffusermentioning

confidence: 99%