Mechanism And Experiment Study Of Piezoelectrical Fluid Energy Harvester Based On Bluffbody Excitation

As technology and the economy continue to advance,the need of data collection and analysis is becoming more urgent;in addition,the climate and environmental problems caused by the irrational use of energy become increasingly serious.Using clean energy in the environment for power self-supply of sensors,on the one hand it could reduce the dependence on the grid and batteries,so that the sensors could be arranged beyond the coverage of the grid,to achieve a larger range of data acquisition and measurement;on the other hand it could avoid the extra cost and environmental pollution problems caused by batteries.As the current hot research content,the energy conversion mechanisms of energy harvesting include piezoelectric mechanism,electromagnetic mechanism,and electrostatic mechanism（including dielectric elastomer generator and triboelectric nanogenerator）,etc.In this paper,under the piezoelectric mechanism with bluffbody excitation induced by fluid,the fluid energy harvesting and conversion with bluffbody fixed type and bluffbody cantilever beam type fluid piezoelectric energy harvester was studied,the threshold of the harvester was lowered to some extent,the flow speed could be sensed and measured by the harvester,and power other low-power small sensing devices.Firstly,this paper summarizes the current research status of piezoelectric energy harvester with bluffbody excitation and magnetometric nonlinearity,conducts the research idea of combining nonlinearity and piezoelectric mechanism,aims at lowering the threshold of the harvester,proposes the teardrop shaped bluffbody fixed type and the irregular shaped bluffbody cantilever beam type fluid piezoelectric energy harvester.The bluffbody fixed type harvester uses Polyvinylidene Fluoride（PVDF）as transducer,which could arise the combination of vortex-induced vibration（VIV）and galloping as bluffbody nonlinearity;the bluffbody cantilever beam type harvester uses piezoelectric with Lead Zironate Titanate Plate（PZT）as transducer,with magnetic nonlinearity to further improve the harvesting efficiency.This paper conducts theoretical and simulative analyses of two harvesters,provides preliminary verification for the structural parameter optimization,and lays the foundation for the subsequent performance test and the outdoor environmental power supply test.Based on two fluid piezoelectric energy harvesters,the experimental platform are constructed,the peak-to-peak output voltage and the output power are selected as the harvester output performance measures to conduct test.For the bluffbody fixed type energy harvester,with inlet angle I 40°,PVDF angle P 10°,outlet angle E 10°,and wind speed 18m/s,the maximum output voltage is 10.42 V_p-p,the output voltage and wind speed have a stable correlation,which could be used as flow velocity sensors for fluid.For the bluffbody cantilever beam type energy harvester,with PZT spacing P 24 mm,magnet spacing M 0 mm,bluffbody R2,wind speed 5.5 m/s,and resistance 800 kΩ,the maximum voltage of PEH 1and 2 are 33.42 V_p-p,33.72 V_p-p,the maximum output power are 0.344 m W,0.346 m W respectively,which could power light-emitting diodes（LED）,and low-power small temperature&humidity sensors,provide a viable solution for the application of fluid piezoelectric energy harvester in practical environments.