Effect of shroud on the performance of horizontal axis hydrokinetic turbines

Shahsavarifard, Mohammad; Bibeau, Eric; Chatoorgoon, Vijay

doi:10.1016/j.oceaneng.2014.12.006

Cited by 56 publications

(31 citation statements)

References 104 publications

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“…For all flow speeds, the optimal TSR was between 3 and 4. This is roughly consistent with previously published results [3,6].…”

Section: B Experimental Resultssupporting

confidence: 94%

“…In theory, a shroud will increase the fluid velocity through the turbine and reduce blade tip losses [3]. Shrouds also have the secondary benefit of providing some degree of physical protection to the turbine blades.…”

Section: Hydrokinetic Turbine Fundamentalsmentioning

confidence: 99%

“…Gaden and Bibeau [5] conducted numerical studies modeling the turbine as a momentum source, and showed significant improvement in power output through use of a diffusing shroud. Shahsavarifard, Bibeau, and Birjandi [3] conducted an experimental study of two different shroud profiles: one convergent-divergent, and one purely divergent. Tests were conducted in a variable speed water tunnel at the University of Manitoba and provided a solid set of experimental data useful for validating future theoretical or numerical models.…”

Section: Hydrokinetic Turbine Fundamentalsmentioning

confidence: 99%

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Experimental and numerical study on performance of shrouded hydrokinetic turbines

Gish

Hawbaker

2016

OCEANS 2016 MTS/IEEE Monterey

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Abstract-Hydrokinetic turbines, also known as marine current turbines, have the potential to be a major component of the world's renewable energy portfolio. Improving the efficiency of turbines is critical to making this technology more widespread and cost-effective. This work focused on raising power output for a given turbine blade design and flow speed through the addition of a straight-diffusing shroud. A shroud works by lowering pressure at the turbine outlet and thereby accelerating the flow through the turbine. The performance (measured by the power coefficient, CP) of a shrouded horizontal axis hydrokinetic turbine was studied experimentally in a tow tank at the United States Naval Academy. Two different shroud designs were built and tested, and performance was compared to the bare turbine. Both shrouds featured the same diffuser angle (20 0 ) but different area ratios, cross-sectional shapes, and tip gaps. The second shroud design was optimized using numerical flow simulation data, and resulted in a 21% increase in power output compared to the bare turbine. Both shroud designs lowered the stall speed of the turbine and allowed operation at lower tip speed ratios.

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“…For all flow speeds, the optimal TSR was between 3 and 4. This is roughly consistent with previously published results [3,6].…”

Section: B Experimental Resultssupporting

confidence: 94%

Section: Hydrokinetic Turbine Fundamentalsmentioning

confidence: 99%

Section: Hydrokinetic Turbine Fundamentalsmentioning

confidence: 99%

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Experimental and numerical study on performance of shrouded hydrokinetic turbines

Gish

Hawbaker

2016

OCEANS 2016 MTS/IEEE Monterey

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“…In addition, a drag force (dD) is done in the flow direction. The drag force is due to both viscous friction forces at the surface of the hydrofoil and the unequal pressure on the hydrofoil surface facing toward and away from the oncoming flow . The terms dL and dD can be found from the definition of the lift (C L ) and drag (C D ) coefficients as follows:

d L = C_{L} \frac{1}{2} ρ {V_{R e l}}^{2} c d r

d D = C_{D} \frac{1}{2} ρ {V_{R e l}}^{2} c d r

…”

Section: Design Of the Hydrokinetic Turbinementioning

confidence: 99%

Influence of the diffusor angle and a damper opening angle on the performance of a hydrokinetic turbine

Chica

Pérez

Rubio-Clemente

2017

Env Prog and Sustain Energy

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Computational fluid dynamic (CFD) technique has been used to investigate the effect of the diffuser expansion angle on the power coefficient of a hydrokinetic turbine. The performance coefficient was compared to that of a conventional bare hydrokinetic turbine of 1 Hp (746 W) designed for a water velocity of 1.5 m s−1 with a tip speed ratio of 6.325; an attack and pitch angle of 5 and 0 degrees, respectively; a power coefficient of 0.4382; a drive train efficiency of 70% and a S822 airfoil profile. The CFD results showed that the extracted power of the hydrokinetic turbine with diffuser can be larger than the power extracted by a bare turbine with the same area. Nevertheless, the level of stress on the blade structure was also increased due to the hydrokinetic turbine with diffuser was exposed to a larger structural loading condition by the water flow. Additionally, the numerical analysis of a damper located at the exit of the turbine diffuser was developed. It was observed that when the opening angle of the damper is between 0 and 20 degrees, an increase in the mass flow through the turbine blades is achieved, resulting in a slight increase in the power coefficient. © 2017 American Institute of Chemical Engineers Environ Prog, 37: 824–831, 2018

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“…The tidal power system was one of the first ocean energy technologies to be commercialized. In the 1960s, a large-scale barrage was built in La Rance, France and small-scale tidal turbines, have also been prototyped for research purposes [1,2]. The kinetic energy from the moving water drives a tidal turbine, which is then converted from the mechanical energy to electrical energy by a generator, then transfering the electricity produced to an onshore power station through underwater power cables [3].…”

Section: Introductionmentioning

confidence: 99%