Efficiency-based design optimization of the H-type Darrieus wind turbine with fixed guiding-walls

In this work, metamodeling was performed to conduct efficiency-based design optimization (EBDO) of an H-rotor VAWT coupled with fixed guiding-walls surrounding its rotor. A design of experiments (DoE) created sampling points from the desired design space. Kriging generated surrogate models using input and output pairs calculated by CFD analyses. The Nelder–Mead Downhill Simplex optimization technique was used to determine the optimal design which satisfied the stated constraints. An estimated level of uncertainty was assigned to each random design variable for the efficiency analyses. Designing of guiding walls were considered, with different geometrical parameters. The results of the surrogate model were compared with those of the CFD, and an optimal solution was selected. The Open Darrieus VAWT and Optimal Darrieus​ VAWT with guiding-walls comparison revealed a considerable improvement of up to 177% at λ=3. It was evident that the enhancement in power coefficient due to augmentation of airflow velocity when VAWT is equipped with guiding walls. As a result, the placement and formation of the guiding walls has a significant role in the amount of power produced.