Enhancement of performance of wave turbine during stall using passive flow control: first and second law analysis

Ahmed Shehata, Qing Xiao, Mohamed M. Selim, A.H. Elbatran, Alexander Day

Research output: Contribution to journalArticle

10 Citations (Scopus)

Abstract

Wells turbine is the most common type of self-rectifying air turbine employed by Oscillating Water Column (OWC) wave energy devices due to its technical simplicity, reliability, and design robustness. Because it subjected to early stall, there were many endeavors to improve the energy extraction performance of Wells turbine within the stall regime. Using the multi suction slots as a passive flow control can help obtaining a delayed stall. Two, three and four suction slots were investigated to improve the performance of Wells turbine in the stall regime. In addition the commonly used first law analysis, the present study utilized an entropy generation minimization method to examine the impact of the multi suction slots method on the entropy generation characteristics around the turbine blade. The turbine blade with optimum suction slots number and location was investigated using the oscillating water system based on the real data from the site. To achieve this purpose, two-dimension numerical models for Wells turbine airfoils under sinusoidal wave flow conditions were built and analyze using (ANSYS FLUENT) solver. It is found that the airfoil with three suction slots located at 40%, 55% and 90% from leading edge in chord percentage give the highest torque coefficient by 26.7% before the stall and 51% after the stall.
LanguageEnglish
Pages369-392
Number of pages24
JournalRenewable Energy
Volume113
Early online date4 Jun 2017
DOIs
Publication statusPublished - 31 Dec 2017

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Flow control
Turbines
Airfoils
Turbomachine blades
Entropy
Compressed air motors
Water
Numerical models
Torque

Keywords

  • oscillating flow
  • wells turbine
  • flow control method
  • entropy generation
  • Egyptian coasts
  • oscillating water column
  • suction slots
  • torque coefficient

Cite this

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title = "Enhancement of performance of wave turbine during stall using passive flow control: first and second law analysis",
abstract = "Wells turbine is the most common type of self-rectifying air turbine employed by Oscillating Water Column (OWC) wave energy devices due to its technical simplicity, reliability, and design robustness. Because it subjected to early stall, there were many endeavors to improve the energy extraction performance of Wells turbine within the stall regime. Using the multi suction slots as a passive flow control can help obtaining a delayed stall. Two, three and four suction slots were investigated to improve the performance of Wells turbine in the stall regime. In addition the commonly used first law analysis, the present study utilized an entropy generation minimization method to examine the impact of the multi suction slots method on the entropy generation characteristics around the turbine blade. The turbine blade with optimum suction slots number and location was investigated using the oscillating water system based on the real data from the site. To achieve this purpose, two-dimension numerical models for Wells turbine airfoils under sinusoidal wave flow conditions were built and analyze using (ANSYS FLUENT) solver. It is found that the airfoil with three suction slots located at 40{\%}, 55{\%} and 90{\%} from leading edge in chord percentage give the highest torque coefficient by 26.7{\%} before the stall and 51{\%} after the stall.",
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author = "Ahmed Shehata and Qing Xiao and Selim, {Mohamed M.} and A.H. Elbatran and Alexander Day",
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Enhancement of performance of wave turbine during stall using passive flow control : first and second law analysis. / Shehata, Ahmed; Xiao, Qing; Selim, Mohamed M.; Elbatran, A.H. ; Day, Alexander.

In: Renewable Energy, Vol. 113, 31.12.2017, p. 369-392.

Research output: Contribution to journalArticle

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AU - Xiao, Qing

AU - Selim, Mohamed M.

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AU - Day, Alexander

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N2 - Wells turbine is the most common type of self-rectifying air turbine employed by Oscillating Water Column (OWC) wave energy devices due to its technical simplicity, reliability, and design robustness. Because it subjected to early stall, there were many endeavors to improve the energy extraction performance of Wells turbine within the stall regime. Using the multi suction slots as a passive flow control can help obtaining a delayed stall. Two, three and four suction slots were investigated to improve the performance of Wells turbine in the stall regime. In addition the commonly used first law analysis, the present study utilized an entropy generation minimization method to examine the impact of the multi suction slots method on the entropy generation characteristics around the turbine blade. The turbine blade with optimum suction slots number and location was investigated using the oscillating water system based on the real data from the site. To achieve this purpose, two-dimension numerical models for Wells turbine airfoils under sinusoidal wave flow conditions were built and analyze using (ANSYS FLUENT) solver. It is found that the airfoil with three suction slots located at 40%, 55% and 90% from leading edge in chord percentage give the highest torque coefficient by 26.7% before the stall and 51% after the stall.

AB - Wells turbine is the most common type of self-rectifying air turbine employed by Oscillating Water Column (OWC) wave energy devices due to its technical simplicity, reliability, and design robustness. Because it subjected to early stall, there were many endeavors to improve the energy extraction performance of Wells turbine within the stall regime. Using the multi suction slots as a passive flow control can help obtaining a delayed stall. Two, three and four suction slots were investigated to improve the performance of Wells turbine in the stall regime. In addition the commonly used first law analysis, the present study utilized an entropy generation minimization method to examine the impact of the multi suction slots method on the entropy generation characteristics around the turbine blade. The turbine blade with optimum suction slots number and location was investigated using the oscillating water system based on the real data from the site. To achieve this purpose, two-dimension numerical models for Wells turbine airfoils under sinusoidal wave flow conditions were built and analyze using (ANSYS FLUENT) solver. It is found that the airfoil with three suction slots located at 40%, 55% and 90% from leading edge in chord percentage give the highest torque coefficient by 26.7% before the stall and 51% after the stall.

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