Research On Energy Harvesting Ability Of Flexible Peizoelectric Material Under Water

In the nature, the flow of the fluid contains abundant energy and we havebeen able to transform wind energy and hydroenergy to electrical energy for ourproduction and livelihood. When fluid impacts on piezoelectric materials,piezoelectric materials will vibrate and the kinetic energy of fluid will betransformed to electrical energy, hence, the technology of the flow-inducedvibration and energy harvesting using piezoelectric materials is becoming aresearch hotspot gradually. With the development of flexible piezoelectricmaterials, they are widely used in the research of the flow-induced vibration andenergy harvesting using piezoelectric materials. Deformation of the flexiblepiezoelectric materials take place easily and its energy conversion efficiency ishigh in vortex field compare with that in placid flow field. Therefore, thetechnology of the flow-induced vibration and energy harvesting using flexiblepiezoelectric materials in vortex field has a huge research significance.In this paper, according to the theory of flow around cylinders, the theoryof vortex motion, the theory of vibration and piezoelectric etc., thecharacteristics of flexible piezoelectric materials in vortex field is explored.This paper composed of following works:Firstly, according to the theory of flow around cylinders and the theory ofvortex motion, the characteristics of the piezoelectric vibrator’ force in vortexfield is analyzed. Based on the theory of vibration of beam in liquid, added massand resulting damping coefficient of the piezoelectric vibrator, which is causedby the liquid, are studied. And then, the mathematical model of piezoelectricenergy harvester about flexible piezoelectric materials in vortex field isestablished.Secondly, the characteristics of the energy harvesting of flexiblepiezoelectric vibrator in vortex field are studied from three aspects, includingdifferent water flow velocity, different cylinder’s diameter and different size ofthe piezoelectric vibrator. The results show that the increase of both water flowvelocity and cylinder’s diameter can lead to increase of the power generationcapacity of the flexible piezoelectric vibrator. In addtion, the piezoelectricvibrator is larger, the power generation capacity is better.Finally, the experimental system is established to validate the theoreticalresults. In the experiment, Macro Fiber Composite are used. The effect of water flow velocity and cylinder’s diameter on the power generation capacity of theflexible piezoelectric vibrator are explored. The results of experiment conformto the theoretical results basically.