Optimization of energy harvesting performance of semi-active flapping airfoil power generator based on orthogonal experiment method

Abstract

ABSTRACT In order to explore the energy harvesting performance of the semi-active flapping airfoil, a new semi-active flapping airfoil power generator (FAPG) using the coupling of the ratchet and gear pinion as transmission mechanism was developed. The influence of the pitching amplitudes, pitching axis positions, and pitching periods on the energy harvesting performance of the semi-active FAPG was explored systematically by the orthogonal experiment and computational fluid dynamics simulation method. The experimental results indicated that the pitching amplitude, pitching axis position, and pitching period can significantly influence the energy harvesting performance of the semi-active FAPG. Under wind speed of 3, 4, and 5 m/s, the mean net output power of the semi-active FAPG reaches 0.026, 0.0297, and 0.0318 W, respectively. It was also found that compared with the pitching amplitude and the pitching axis position, the pitching period has the greatest influence on the mean net output power. Through the deep analysis of the flow fields around the semi-active flapping airfoils with different parameter combinations, it was found that the optimized parameter combinations can delay the shedding of the trailing edge vortex generated by the flapping airfoil during pitching motion, and make the separated leading edge vortex generated during the plunging motion reattaching again on the surface of the flapping airfoil, which leads to have better energy harvesting performance of the generator.