scholarly journals Hydrodynamic Assessment of a Dual-Rotor Horizontal Axis Marine Current Turbine

2018 ◽  
Vol 7 (4.10) ◽  
pp. 455 ◽  
Author(s):  
EJ Avital ◽  
K Ai ◽  
N Venkatesan ◽  
A Samad ◽  
T Korakianitis
Keyword(s):  
Horizontal Axis ◽  
Hydrodynamic Performance ◽  
Medium Size ◽  
Speed Ratio ◽  
Power Gain ◽  
Performance Variation ◽  
Marine Current Turbine ◽  
Marine Current ◽  
Wake Model ◽  
Current Turbine

The hydrodynamic performance of a dual-rotor horizontal axis marine turbine (HAMCT) is investigated for the power gain in operating the rear rotor without blade-pitch control. This kind of turbine can be advantageous for a rectilinear tidal current of reversing directions, where each rotor blade is optimally fixed-pitched towards its upstream velocity. The blade element momentum (BEM) method is coupled with the Park wake model. A generic three-blade turbine is shown to gain up to 20% in the coefficient of power CP as relative to the front rotor CP when operating the rear rotor at the same tip speed ratio (TSR) as the front one, gaining overall CP up to 0.55. Analytic model is derived to backup the estimate of power gain. Plots for turbine performance variation with TSR and profile hydrodynamic efficiency are given, and analysed for lab and small-medium size turbines.  

Hydrodynamic Analysis of a Horizontal Axis Marine Current Turbine With a Boundary Element Method

2008 ◽  
Author(s):  
J. Baltazar ◽  
J. A. C. Falca˜o de Campos
Keyword(s):  
Horizontal Axis ◽  
Model Parameters ◽  
Viscous Effects ◽  
Pressure Distributions ◽  
Marine Current Turbine ◽  
Wide Range ◽  
Marine Current ◽  
Line Theory ◽  
Wake Model ◽  
Current Turbine

A low order potential based panel code is used to analyse the flow around the blades of a horizontal axis marine current turbine. An empirical vortex model is assumed for the turbine wake which includes the variation of pitch of the helicoidal vortices trailing behind the blades. The analysis is carried out for uniform inflow conditions in steady flow for a turbine with controllable pitch for two different pitch settings in a wide range of tip-speed-ratios. Grid convergence studies carried out to verify the accuracy of predicted pressure distributions and integrated forces show a fast convergence with grid refinement for this geometry. The effect of the helicoidal wake model parameters used in the analysis is found to have a strong influence in the performance curves. The results are compared with experimental data from the literature and with the lifting line theory. A discussion of viscous effects is also provided to help explaining the main discrepancies with the data.

Hydrodynamic Analysis of a Horizontal Axis Marine Current Turbine With a Boundary Element Method

2011 ◽  
Vol 133 (4) ◽  
Author(s):  
J. Baltazar ◽  
J. A. C. Falcão de Campos
Keyword(s):  
Horizontal Axis ◽  
Model Parameters ◽  
Viscous Effects ◽  
Pressure Distributions ◽  
Marine Current Turbine ◽  
Wide Range ◽  
Marine Current ◽  
Line Theory ◽  
Wake Model ◽  
Current Turbine

A low order potential based panel code is used to analyze the flow around the blades of a horizontal axis marine current turbine. An empirical vortex model is assumed for the turbine wake, which includes the variation of pitch of the helicoidal vortices trailing behind the blades. The analysis is carried out for uniform inflow conditions in steady flow for a turbine with controllable pitch for two different pitch settings in a wide range of tip-speed-ratios. Grid convergence studies carried out to verify the accuracy of predicted pressure distributions and integrated forces show a fast convergence with grid refinement for this geometry. The effect of the helicoidal wake model parameters used in the analysis is found to have a strong influence in the performance curves. The results are compared with experimental data from literature and with the lifting line theory. A discussion of viscous effects is also provided to help explaining the main discrepancies with the data.

Augmented Diffuser for Horizontal Axis Marine Current Turbine

2016 ◽  
Vol 7 (1) ◽  
pp. 235 ◽  
Author(s):  
Aly Hassan Elbatran ◽  
Omar Yaakob ◽  
Yasser Ahmed ◽  
Firdaus Abdallah
Keyword(s):  
Tidal Current ◽  
Renewable Energy Sources ◽  
Research Work ◽  
Horizontal Axis ◽  
Offshore Wind ◽  
Water Current ◽  
Maximum Efficiency ◽  
Marine Current Turbine ◽  
Marine Current ◽  
Current Turbine

<span>The potential of renewable energy sources is enormous as they can make a major contribution to the future of energy needs. The ocean has a great potential to become a practical and predictable energy source compared to other energy resources such as solar, wind, and nuclear. It offers different sources of energy which can be utilized namely wave, tidal, offshore wind, thermal, and tidal current. Among these sources, marine tidal current has major advantages such as higher power availability and predictability. The main objective of this research work is to design and develop a horizontal axis marine current turbine (HAMCT) that suitable for operating within Malaysian ocean, which has low speed current (0.5 – 1 m/s average). A prototype of augmented diffuser 4-bladed HAMCT applying NACA 0014 was proposed in the current study. The turbine model has 0.666 m diameter, and it was designed to produce as much as power from flowing water current. Model was constructed and tested at Marine Technology Center (MTC) in three conditions, namely, free tow testing, ducted tow testing, and ducted diffuser tow testing in order to predict the power and efficiency of the turbine system. The results showed that the application of duct was significant to concentrate the flow and diffuser arrangement was effective when it was placed behind of the rotor in this condition of low water current speed. The maximum efficiency Cp obtained in the current system was 0.58.</span>

Numerical Predictions and Experimental Verifications for the Hydrodynamic Performance of Horizontal Axis Marine Current Turbine

2013 ◽  
Vol 694-697 ◽  
pp. 635-638
Author(s):  
Rui Jun Fan ◽  
Hong Chao Gao ◽  
J. R. Chaplin
Keyword(s):  
Hydrodynamic Performance ◽  
Experimental Measurements ◽  
Hydrodynamic Conditions ◽  
Towing Tank ◽  
Numerical Predictions ◽  
Turbine Performance ◽  
Marine Current Turbine ◽  
Cavitation Tunnel ◽  
Marine Current ◽  
Current Turbine

This paper presents the numerical predictions of 3D CFD rotor computations of an 800mm diameter model of marine current turbine (MCT). In the paper CFD is applied to a rotor at stationary hydrodynamic conditions Simulations from the numerical prediction are compared with experimental measurements of the model of MCT which is experimented on in a cavitation tunnel and a towing tank. The experimental data includes measurements of power and thrust generated by the turbine, in both a cavitation tunnel and a towing tank, for a series of blade pitch settings and speeds. The numerical predictions show similar results and provide a satisfactory representation of the experimental turbine performance.

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