Theoretical modeling, wind tunnel measurements, and realistic environment testing of galloping-based electromagnetic energy harvesters

摘要

Extracting energy from environmental airflows and converting it into usable electricity can be a potential approach to realize the self-powering operation of sensors by virtue of energy harvesting technology, which has received great interest in recent years. Yet the environmental adaptability and the level of output power are two of important aspects to restrict wide applications of energy harvesters and hence still required to be improved. For this purpose, a novel and efficient electromagnetic energy harvester for airflow power generation is designed, and a theoretical model is constructed and experimentally verified to characterize the design and output performance of the energy harvester. To this end, a bluff body with the cross-section of Y-shape subjected to airflows is considered. Then, the aeroelastic response of bluff body occurs and brings the coil to cut magnetic induction lines. The experimental results show that an average power of 2.5 mW is measured at wind speed of 4 m/s, which is dominant compared to existing aeroelastic energy harvesters. Furthermore, charging and discharging experiments demonstrate 30 s of airflow in wind tunnel under speed of 3.5 m/s can drive the sensor of 1.1 V working voltage to operate for about one minute. In addition, it is significant that the harvester's environmental adaptability is revealed under condition of the air-conditioner vent. The present research offers a suggestive guidance on developing an efficient electromagnetic energy harvester for airflow power generation, at the same time it further promotes the realization of self-powering of structural health monitoring sensors applying in buildings and bridges.