Single-objective optimization design of convergent-divergent ducts of ducted wind turbine using RSM and GA, to increase power coefficient of a small-scale horizontal axis wind turbine

• Published in: Energy (Oxford) Vol. 269; p. 126822
• Main Authors: Rahmatian, Mohammad Ali, Nazarian Shahrbabaki, Amin, Moeini, Seyed Peyman
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 15.04.2023
• Subjects: Convergent-divergent duct; Design of experiments (DOE); Genetic algorithm (GA); Horizontal axis wind turbine; Numerical study; Optimization; Response surface method (RSM); Genetic algorithm (GA); Horizontal axis wind turbine; Design of experiments (DOE); Response surface method (RSM); Convergent-divergent duct; Optimization; Numerical study
• ISSN: 0360-5442
• DOI: 10.1016/j.energy.2023.126822

Nowadays, considering the importance of energy and the important role of wind in energy production, the present study investigates increasing the power coefficient of wind turbines by adding a convergent-divergent duct to them and optimizing the duct components. The primary duct consists of two components, a diffuser and a flange, to which a nozzle is added to the beginning of the diffuser. In this study, in the first step, 79 different geometries (three-dimensional) were defined using the design of experiments (DOE) and examined using the numerical method. Then, the output results are coupled by the response surface method (RSM) and genetic algorithm (GA) and the duct geometry is optimized. In this optimization process, 7 parameters including the length and angle of the duct components (nozzle, diffuser, and flange) and the throat diameter are investigated simultaneously. The objective functions in this optimization process are the maximum velocity and the maximum average velocity at the duct throat. In the second step, a horizontal axis wind turbine is placed inside the optimal duct and the gap between the blade tip and the duct is examined. The novelty of the present study is the simultaneous optimization of the length and angle of all components of a convergent-divergent duct, which has not been studied so far. The results show that the wind speed increases up to 2.18 times and the wind turbine power coefficient increases up to 3.94 times at the throat. Also, the results show that the presence of the duct breaks the vortices behind the turbine, which reduces the noise level and dynamic forces generated by the rotor. As a result, an auxiliary rotor or other structure can be used behind the turbine. •Convergent-divergent duct optimization using RSM and GA.•Optimize the gap between the blade tip and the duct.•Increase 2.18 times the local wind speed and increase the wind turbine power coefficient up to 3.94 times by the optimal duct.