Renewable Energy Resources and Technologies
Saeed Karimian Aliabadi; Saber Rezaey
Abstract
The INVELOX system is an innovative approach that offers improved energy absorption efficiency from wind flow and reduced costs by utilizing smaller wind turbines. This research focuses on investigating the steady-state performance of one, two, or three wind turbines arranged within the venturi section ...
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The INVELOX system is an innovative approach that offers improved energy absorption efficiency from wind flow and reduced costs by utilizing smaller wind turbines. This research focuses on investigating the steady-state performance of one, two, or three wind turbines arranged within the venturi section of the system. A comprehensive modeling approach using an improved Blade Element Momentum (BEM) theory is proposed and implemented as a MATLAB code. The code incorporates Prandtl's tip and hub loss factors, as well as turbulent wake corrections. The accuracy of the code is validated against experimental and numerical data. The results demonstrate that in a three-rotor tandem configuration in the INVELOX system, the power extracted from the second and third turbines is 0.54 and 0.24 times the power of the first turbine, respectively. Furthermore, for a two-turbine arrangement in the venturi section, the total power extracted from the system is 53.9% higher than that of a single turbine layout. In the case of a three-turbine configuration, the total power increases up to 1.78 times compared to a single turbine. The proposed model is suitable for geometric optimization and parameter studies. The system's performance is evaluated in terms of tip speed ratio, and the effects of different correction models are analyzed, including the local changes in forces and moments.
Renewable Energy Resources and Technologies
Saeed Karimian Aliabadi; Sepehr Rasekh
Abstract
In this study, an unsteady aerodynamic simulation is performed to realize the influences of platform surge motion on the aerodynamic performance of a high capacity offshore floating wind turbine. A dynamic model with pitch angle control system is utilized to propose a more realistic model of wind turbine ...
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In this study, an unsteady aerodynamic simulation is performed to realize the influences of platform surge motion on the aerodynamic performance of a high capacity offshore floating wind turbine. A dynamic model with pitch angle control system is utilized to propose a more realistic model of wind turbine and also achieve the rated condition of the rotor. The transient effect of platform surge motion on power coefficient, thrust coefficient and blade pitch angle also is investigated. The 5 MW NREL wind turbine is selected for the simulations. The unsteady aerodynamic model contains unsteady blade element momentum method, dynamic stall and dynamic inflow models. The in-home aerodynamic code and the control system model are implemented in MATLAB/SIMULINK software. It is revealed that reduction in mean power coefficient at tip speed ratios less that 7 is expected by amount of 12-15 % at surge amplitude of 2m and frequency of 0.1 Hz. For high tip speed ratios, the trend is reverse with respect to fixed-platform case. The mean thrust coefficient is also reduced for many tip speed ratios with maximum loss of 32 %. The mean blade control pitch angle is increased due to the surge motion. Since the influence of changing amplitude and frequency of disturbances depends on the tip speed ratio, therefore the special bound of this parameter is being proposed.
