Study On Piezoelectric Airflow Energy Harvester Based On Resonant Cavity

In order to achieve real-time monitoring of state and energy self-sufficiency of remote control system nodes,a cavity piezoelectric air-generator is proposed in this paper.The output characteristics of the generator are studied in both theory and experiment.The specific research work and conclusions are as follows:A COMSOL simulation model of a circular piezoelectric vibrator was established.The radius ratio(the ratio of the radius of the ceramic plate to the radius of the substrate),the ratio of the thickness(the ratio of the thickness of the substrate to the total thickness of the piezoelectric vibrator),and the size of the uniform load were analyzed.The effect of the natural frequency of the oscillator.Through the simulation analysis,the relationship curve of the natural frequency of the piezoelectric vibrator under different radius,uniform load and thickness ratio of the metal substrate and radius ratio,and the relationship between the thickness of the piezoelectric ceramic and the thickness of the piezoelectric vibrator are obtained.The COMSOL modelling process of cavity piezoelectric generator is introduced.The output characteristics of three piezoelectric air generators without cavity,single cavity and compound cavity under different structural parameters are simulated.Three kinds of-cavity are obtained under different air flow rates.The output characteristics of the piezoelectric gas turbine generator show that:① The deformation of the piezo electric vibrator with no cavity piezoelectric generator increases first and then decreases with the increase of the excitation distance;②the piezoelectric vibrator of a single cavity piezoelectric generator The deformation increases first and then decreases with the increase of the cavity length;③ there is an optimal length of the neck that makes the displacement of the piezoelectric vibrator of the composite cavity piezoelectric generator the largest.A prototype of a cavity-free,single-cavity,composite-cavity piezo-electric generator was designed and built.A test platform was set up to test and the output performance of three types of generators under different parameters was obtained.The airflow speed and external load were also explored.Influence of Neck Length on OLutput Power of Piezoelectric Airflow Generator in Composite Cavity.The results show that:①There is an optimal excitation distance at the given pressure of the gas flow,which makes the output voltage of the piezoelectric-air generator without cavity maximum.②The optimum cavity length for the given gas flow pressure makes the output voltage of the single cavity piezoelectric air generator reach the maximum value.③The optimum sub-cavity diameter for the given pressure of the air flow makes the output voltage of the piezoelectric air generator in the composite chamber maximum;when the pressure of the air flow is low(p<0.3 MPa),there is an optimal sub-cavity length to maximize the output voltage;When the height is higher(p>0.3 MPa),the output voltage increases as the length of the sub cavity decreases;when the length of the main cavity is less than 60 mm,there is an optimal ratio of the length of the main cavity to the sub cavity so that the output voltage is maximum.and when the length of the main cavity is greater than 60 mm,The output voltage increases with the length ratio of the main and auxiliary chambers.The effects of air flow velocity,external load,and neck lengt on the output power of the piezoelectric air generator in the composite chamber were studied.The results show that when the pressure/sub-cavity is constant,there is an optimal external load to maximize the output power;when the external load is fixed,the output power increases with the pressure of the air flow;when the external load is constant,the output power and the length of the neck Inversely.