Investigation of the Performance of a Bioinspired Two-Fold Blades Wind Turbine with Airfoil Blade Sections by Using QBlade

The current study focuses on the investigation of the power and thrust performance of a new two-fold blades wind turbine design by using blade element momentum (BEM) based wind turbine analytical software, namely the QBlade. The two-fold blades wind turbine is a downwind, 3-bladed airfoiled wind turbine that consists of a root fold axis and a mid-span fold axis. The blade sections are shaped by using the SD8000 airfoil. The idea of folding the straight blade wind turbine was inspired by the winged seed of the Borneo Camphor tree (Dryobalanops aromatica), which consists of wings that are folded. It was presumed that the folding of the wind turbine blades would alter the pitch and cone angles of the blade sections, which consequently affect the angle of attack, changing its power and thrust performance. Fixed fold axis angles and two levels of fold angles were applied to the root and mid-span fold axis. The unfolded wind turbine blade was also the benchmark wind turbine adopted from the study conducted by a previous researcher. This unfolded wind turbine blade was with the size of one meter in diameter and with a constant chord length of 90 mm throughout the span. The fold at the root made the blade tilt towards the downstream direction, while the mid-span fold tilts the blade tip towards the upstream direction in an attempt to mimic the folding pattern of the wings of Borneo Camphor seed. The analytical results show that under the wind speed of 10 m/s, the proposed two-fold blades wind turbine outperformed the benchmark (unfolded) wind turbine at low tip speed ratios. Thus, this confirms the potential application of the two-fold blade wind turbine design in the wind energy industry, where it can be used in power regulation through folding mechanisms.