Performance analysis of wells turbine blades using the entropy generation minimization method

Ahmed S. Shehata, Khalid M. Saqr, Qing Xiao, Mohamed F. Shehadeh, Alexander Day

Research output: Contribution to journalArticle

21 Citations (Scopus)

Abstract

Wells turbine concept depends on utilizing the oscillating air column generated over marine waves to drive a turbine. As a matter of fact, previous researches on the performance analysis of such turbine were based on the first law of thermodynamics only. Nonetheless, the actual useful energy loss cannot be completely justified by the first law because it does not distinguish between the quantity and the quality of energy. Therefore, the present work investigates the second law efficiency and entropy generation characteristics around different blades that are used in Wells turbine under oscillating flow conditions. The work is performed by using time-dependent CFD models of different NACA airfoils under sinusoidal flow boundary conditions. Numerical investigations are carried out for the incompressible viscous flow around the blades to obtain the entropy generation due to viscous dissipation. It is found that the value of second law efficiency of the NACA0015 airfoil blade is higher by approximately 1.5% than the second law efficiency of the NACA0012, NACA0020 and NACA0021 airfoils. Furthermore, it is found that the angle of attack radically affects the second law efficiency and such effect is quantified for NACA0015 for angle of attack ranging from -15° to 25°.

LanguageEnglish
Pages1123-1133
Number of pages11
JournalRenewable Energy
Volume86
Early online date29 Sep 2015
DOIs
Publication statusPublished - Feb 2016

Fingerprint

Turbomachine blades
Turbines
Entropy
Airfoils
Angle of attack
Oscillating flow
Viscous flow
Energy dissipation
Computational fluid dynamics
Boundary conditions
Thermodynamics
Air

Keywords

  • CFD
  • entropy generation
  • NACA airfoils
  • sinusoidal wave
  • Wells turbine

Cite this

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title = "Performance analysis of wells turbine blades using the entropy generation minimization method",
abstract = "Wells turbine concept depends on utilizing the oscillating air column generated over marine waves to drive a turbine. As a matter of fact, previous researches on the performance analysis of such turbine were based on the first law of thermodynamics only. Nonetheless, the actual useful energy loss cannot be completely justified by the first law because it does not distinguish between the quantity and the quality of energy. Therefore, the present work investigates the second law efficiency and entropy generation characteristics around different blades that are used in Wells turbine under oscillating flow conditions. The work is performed by using time-dependent CFD models of different NACA airfoils under sinusoidal flow boundary conditions. Numerical investigations are carried out for the incompressible viscous flow around the blades to obtain the entropy generation due to viscous dissipation. It is found that the value of second law efficiency of the NACA0015 airfoil blade is higher by approximately 1.5{\%} than the second law efficiency of the NACA0012, NACA0020 and NACA0021 airfoils. Furthermore, it is found that the angle of attack radically affects the second law efficiency and such effect is quantified for NACA0015 for angle of attack ranging from -15° to 25°.",
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author = "Shehata, {Ahmed S.} and Saqr, {Khalid M.} and Qing Xiao and Shehadeh, {Mohamed F.} and Alexander Day",
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Performance analysis of wells turbine blades using the entropy generation minimization method. / Shehata, Ahmed S.; Saqr, Khalid M.; Xiao, Qing; Shehadeh, Mohamed F.; Day, Alexander.

In: Renewable Energy, Vol. 86, 02.2016, p. 1123-1133.

Research output: Contribution to journalArticle

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AU - Saqr, Khalid M.

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AU - Day, Alexander

PY - 2016/2

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AB - Wells turbine concept depends on utilizing the oscillating air column generated over marine waves to drive a turbine. As a matter of fact, previous researches on the performance analysis of such turbine were based on the first law of thermodynamics only. Nonetheless, the actual useful energy loss cannot be completely justified by the first law because it does not distinguish between the quantity and the quality of energy. Therefore, the present work investigates the second law efficiency and entropy generation characteristics around different blades that are used in Wells turbine under oscillating flow conditions. The work is performed by using time-dependent CFD models of different NACA airfoils under sinusoidal flow boundary conditions. Numerical investigations are carried out for the incompressible viscous flow around the blades to obtain the entropy generation due to viscous dissipation. It is found that the value of second law efficiency of the NACA0015 airfoil blade is higher by approximately 1.5% than the second law efficiency of the NACA0012, NACA0020 and NACA0021 airfoils. Furthermore, it is found that the angle of attack radically affects the second law efficiency and such effect is quantified for NACA0015 for angle of attack ranging from -15° to 25°.

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