The wells air turbine for wave energy conversion

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Comprehensive Renewable Energy

Multi-objective optimization of the airfoil shape of Wells turbine used for wave energy conversion

In the past twenty years, the use of wave energy systems has significantly increased, generally depending on the oscillating water column (OWC) concept. Wells turbine is one of the most efficient OWC technologies. This article provides an updated and a comprehensive account of the state of the art research on Wells turbine. Hence, it draws a roadmap for the contemporary challenges which may hinder future reliance on such systems in the renewable energy sector. In particular, the article is concerned with the research directions and methodologies which aim at enhancing the performance and efficiency of Wells turbine. The article also provides a thorough discussion of the use of computational fluid dynamics (CFD) for performance modeling and design optimization of Wells turbine. It is found that a numerical model using the CFD code can be employed successfully to calculate the performance characteristics of W-T as well as other experimental and analytical methods. The increase of research papers about CFD, especially in the last five years, indicates that there is a trend that considerably depends on the CFD method.

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Wells turbine for wave energy conversion: a review

In this paper, a comparison of total entropy generation between a suggested design and a constant chord Wells turbine is presented. A variable chord rotor Wells turbine design is suggested in order to have a more uniform axial velocity distribution at blades leading edge in comparing conventional design to improve turbine efficiency. Each model is analysed numerically with respect to the total entropy generation due to viscous dissipation around rotor blades. Simulations have been performed by numerical solving of the steady, incompressible, three-dimensional Reynolds-averaged Navier–Stokes together with RNG k–e turbulence model equations in a non-inertial reference frame rotating with the turbine rotor. A comparison of the computed results with the available experimental data exhibits agreement in terms of efficiency, torque and input coefficients at different flow rates. Finally, the detailed comparisons of the results are done between the suggested design and the conventional Wells turbine, demonstrating a 26.02 % average decrease in entropy generation throughout the full operating range, hence supporting the superiority of the new design.

Improved design of Wells turbine for wave energy conversion using entropy generation

A contra-rotating Wells turbine as an alternative to a biplane Wells turbine for wave energy conversion is investigated. The aerodynamic analysis and control of such a turbine are presented. It is shown that for a given pressure amplitude a contra-rotating Wells turbine is aerodynamically more efficient and can operate over a wider range of flowrates when compared to a biplane Wells turbine.

S. Raghunathan

Papers

Aerodynamic Performance of Contra-Rotating Wells Turbine for Wave Energy Conversion

Aerodynamic Performance of Contra-Rotating Wells Turbine For Wave Energy Conversion