LAPSE:2019.0700
Published Article
LAPSE:2019.0700
Theoretical Analysis of Shrouded Horizontal Axis Wind Turbines
July 26, 2019
Numerous analytical studies for power augmentation systems can be found in the literature with the goal to improve the performance of wind turbines by increasing the energy density of the air at the rotor. All methods to date are only concerned with the effects of a diffuser as the power augmentation, and this work extends the semi-empirical shrouded wind turbine model introduced first by Foreman to incorporate a converging-diverging nozzle into the system. The analysis is based on assumptions and approximations of the conservation laws to calculate optimal power coefficients and power extraction, as well as augmentation ratios. It is revealed that the power enhancement is proportional to the mass stream rise produced by the nozzle diffuser-augmented wind turbine (NDAWT). Such mass flow rise can only be accomplished through two essential principles: the increase in the area ratios and/or by reducing the negative back pressure at the exit. The thrust coefficient for optimal power production of a conventional bare wind turbine is known to be 8/9, whereas the theoretical analysis of the NDAWT predicts an ideal thrust coefficient either lower or higher than 8/9 depending on the back pressure coefficient at which the shrouded turbine operates. Computed performance expectations demonstrate a good agreement with numerical and experimental results, and it is demonstrated that much larger power coefficients than for traditional wind turbines are achievable. Lastly, the developed model is very well suited for the preliminary design of a shrouded wind turbine where typically many trade-off studies need to be conducted inexpensively.
Record ID
Keywords
Betz limit, momentum theory, nozzle diffuser augmented, wind lens, wind turbine
Subject
Suggested Citation
Khamlaj TA, Rumpfkeil MP. Theoretical Analysis of Shrouded Horizontal Axis Wind Turbines. (2019). LAPSE:2019.0700
Author Affiliations
Journal Name
Energies
Volume
10
Issue
1
Article Number
E38
Year
2017
Publication Date
2017-01-01
Published Version
ISSN
1996-1073
Version Comments
Original Submission
Other Meta
PII: en10010038, Publication Type: Journal Article
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Published Article
LAPSE:2019.0700
This Record
External Link
doi:10.3390/en10010038
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Version History
[v1] (Original Submission)
Jul 26, 2019
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Jul 26, 2019
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v1
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https://psecommunity.org/LAPSE:2019.0700
Original Submitter
Calvin Tsay
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