Duct and blade design for small-scale floating tidal current turbine development and CFD-based analysis of power performance

Im, Heejeon; Hwang, Tae-Gyu; Kim, Bum Suk

doi:10.1007/s12206-020-0321-2

Cited by 8 publications

(3 citation statements)

References 7 publications

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“…The C Pd,design in DuctA exceeds the Betz limit (0.593) because the turbine is designed as an internal flow. Garrett and Cummins 28 conducted a theoretical investigation of the blockage ratio and showed that the maximum power coefficient for a single turbine at blockage ratio B is (1 2 B) 22 times the Betz limit. To counteract this blockage effect, each power coefficient is multiplied by (1 2 B) 2 , and the corrected values are shown in the filled white plots in the figure.…”

Section: Resultsmentioning

confidence: 99%

“…However, when combined with CFD, the BEM theory becomes more complex, significantly increasing the design time. In addition, most studies of ducted turbines dealt only with one-sided flow 21,22 or simulated the turbine section with an actuator disk, 23,24 and no design method was proposed for a bidirectional turbine. Therefore, a simple design method for bidirectional ducted turbines that can be applied to various duct shapes is required.…”

Section: Introductionmentioning

confidence: 99%

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Design method for a bidirectional ducted tidal turbine based on conventional turbomachinery methods

Tsuru

Kinoue

Murakami

et al. 2023

Advances in Mechanical Engineering

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Renewable energy sources include solar, wind, hydro, geothermal and biomass. Furthermore, ocean energy is being rapidly harnessed worldwide. In this study, to establish a suitable design method for various bidirectional ducted tidal turbines, instead of using blade element momentum theory and CFD, which have been used previously, the method used for turbomachinery was used for designing the turbines. A bidirectional turbine optimises the equipment design and reduces manufacturing and maintenance costs. Using the turbine power as the design condition, the difference in the tangential velocity between the front and rear of the turbine was calculated using Euler’s equation, and the blade stagger angle was determined based on the potential flow theory. To incorporate the effect of duct geometry into this design method in the future, the effect on the internal flow of the duct was experimentally investigated using three ducts with different maximum cross-sectional areas. Performance tests showed that the duct geometry had a negligible effect on the flow rate through the turbine. Therefore, the larger the maximum diameter of the duct, the greater the flow rate into the outside of the duct. The pressure difference between front and rear of the turbine and the inflow energy into the duct were different due to the energy conversion as the flow turned outside of the duct. To improve the accuracy of the design method, the effect of flow at the duct inlet and the energy conversion should be incorporated, and a review of the estimation method for the axial velocity ratio and the selection method for the design representative value should be conducted.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Design method for a bidirectional ducted tidal turbine based on conventional turbomachinery methods

Tsuru

Kinoue

Murakami

et al. 2023

Advances in Mechanical Engineering

View full text Add to dashboard Cite

show abstract

“…Allsop et al [2] used a Blade Element Momentum theory (BEM) model to investigate the behaviour of a ducted open centre turbine, while Zanforlin et al [3] conducted further research: the study utilised 2D CFD to compare the performance of hydrofoil-shaped and symmetrical diffusers for a vertical axis tidal turbine. Im et al [4] created a diffuser for a small, floating tidal turbine and validated its efficacy using BEM theory within an in-house code. An important factor that impacts the harvesting of tidal energy, is that tidal currents typically follow a non-rectilinear path (meaning the inversion every 6 hours is not 180°).…”

Section: Introductionmentioning

confidence: 99%

Behaviour of a tidal turbine system using a diffuser in waters characterized by low speeds and the presence of surface waves typical of the Mediterranean Sea

Pucci,

Zanforlin,

Conte

et al. 2023

J. Phys.: Conf. Ser.

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The exploitation of the kinetic energy of the Mediterranean Sea tidal currents is hindered by low speed values. Therefore, it is useful to investigate methods for accelerating the flow to increase both the power generated by the single machine and the specific power, i.e. related to a certain sea surface. The aim of the study is predicting the power gain achievable by means of a diffuser in very low speed conditions and also to analyse the behaviour of the diffuser in the presence of small amplitude and high frequency surface waves, typical of the Mediterranean. Using 3D CFD simulations we predicted the performance of a system of 2 counter-rotating turbines, coupled side-by-side, equipped with a symmetrical convergent-divergent diffuser. The fluid dynamic interaction with the rotating blades is just mimicked by adopting the momentum source low-order approach, that in our case is based on the Virtual Blade Model (VBM). The diffuser not only enables more than doubled power output, but also dampens the relative fluctuation of torque in case of very low wave amplitude; however, in case of significant amplitudes the turbine angular speed needs to be increased in order to avoid stall, and therefore to preserve the blade structural integrity.

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Hydrodynamic simulation and experiment of depth adjustable beam trawl for Antarctic krill

Zheng

et al. 2023

J Mar Sci Technol

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Duct and blade design for small-scale floating tidal current turbine development and CFD-based analysis of power performance

Cited by 8 publications

References 7 publications

Design method for a bidirectional ducted tidal turbine based on conventional turbomachinery methods

Design method for a bidirectional ducted tidal turbine based on conventional turbomachinery methods

Behaviour of a tidal turbine system using a diffuser in waters characterized by low speeds and the presence of surface waves typical of the Mediterranean Sea

Hydrodynamic simulation and experiment of depth adjustable beam trawl for Antarctic krill

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