Shinya Okuhara¹, Manabu Takao², Hideki Sato³, Akiyasu Takami², Toshiaki Setoguchi⁴

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¹ Support Center for Practical Education, National Institute of Technology, Matsue College, Matsue, Japan.
² Department of Mechanical Engineering, National Institute of Technology, Matsue College, Matsue, Japan.
³ Advanced Engineering Faculty, National Institute of Technology, Matsue College, Matsue, Japan.
⁴ Institute of Ocean Energy, Saga University, Saga, Japan.
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Abstract: As a system using a conventional unidirectional air turbine in oscillating water column (OWC) based on a wave energy plant, a twin unidirectional impulse turbine topology has been suggested in previous studies. However, the average efficiency of the suggested twin turbine is considerably lower than that of a conventional unidirectional turbine in this topology because reciprocating air flow can’t be rectified adequately by a unidirectional turbine. In order to improve the efficiency, using fluidic diode is discussed. In this study, two different fluidic diodes were discussed by computational fluid dynamics (CFD) and a wind tunnel test. Further, its usefulness is discussed from a view point of the turbine efficiency. The fluidic diode was shown to improve rectification of the topology. However, it needs more improvement in regards to its energy loss in order to enhance the turbine efficiency.

Keywords: Fluidic Diode, Twin Unidirectional Turbine, Wave Energy Conversion, Oscillating Water Column

Cite this paper: Okuhara, S. , Takao, M. , Sato, H. , Takami, A. and Setoguchi, T. (2014) A Twin Unidirectional Impulse Turbine for Wave Energy Conversion—Effect of Fluidic Diode on the Performance. Open Journal of Fluid Dynamics, 4, 433-439. doi: 10.4236/ojfd.2014.45033.

References

[1]   Takao, M., Takami, A., Okuhara, S. and Setoguchi, T. (2011) A Twin Unidirectional Impulse Turbine for Wave Energy Conversion. Journal of Thermal Science, 20, 394-397. http://dx.doi.org/10.1007/s11630-011-0486-1

[2]   Dudhgaonkar, P.V., et al. (2011) Fluidic Components for Oscillating Water Column Based Wave Energy Plants. Proceedings of ASME-JSME-KSME Joint Fluids Engineering Conference 2011, Paper No. AJK2011-07035.

[3]   Takebayashi, M., Akazume, A., Yokoyama, K. and Iwata, H. (1984) Discharge Characteristics of a Oil Feeder Pump with Nozzle Type Fluidic Diodes. Transactions of JSME (Series B), 51, 255-261. (In Japanese)

[4]   Okuhara, S., Takao, M., Takami, A. and Setoguchi, T. (2012) A Twin Unidirectional Impulse Turbine for Wave Energy Conversion—Effect of Guide Vane Solidity on the Performance. Open Journal of Fluid Dynamics, 2012, 343-347.
http://dx.doi.org/10.4236/ojfd.2012.24A043

[5]   Takao, M., Setoguchi, T., Kaneko, K., Kim, T.H., Maeda, H. and Inoue, M. (2002) Impulse Turbine for Wave Power Conversion with Air Flow Rectification System. International Journal of Offshore and Polar Engineering, 12, 142-146.