| Smart gas meters and smart water meters replace manual meter reading,reducing the waste of resources,but because of the short life of the chemical battery and the difficulty of manual replacement,the smart gas meters and smart water meters cannot work normally when the power runs out.Therefore,in order to solve the energy supply problem of gas meter and water meter,this paper proposed a piezoelectric energy collection technology based on vorticity vibration,which is easy to miniaturize and pollution-free,and is a reliable and convenient power generation method.This paper studied it from two aspects of simulation and experiment.The main work is as follows:(1)The simulation model of piezoelectric oscillator was established to explore the influence of parameters such as length ratio,thickness ratio and width of piezoelectric oscillator on its surface stress.The relationship between the power generation of piezoelectric oscillator in different vibration modes and the parameters such as length ratio,thickness ratio and width of piezoelectric oscillator and its natural frequency and equivalent stiffness was simulated and analyzed,so as to determine the geometric parameters of piezoelectric oscillator.(2)The lift coefficient and velocity cloud map of different shapes of fluid resistance flow were analyzed.The vortex shedding on both sides of the cylinder resistance fluid was the most stable,which could effectively enhance fluid vibration energy and was most suitable for piezoelectric energy collection.In order to further improve energy output,the vorticity field stimulated by different cylinder resistance fluid diametric was simulated and analyzed.A cylinder with a diameter of 20mm resists fluids to increase system output energy.Secondly,the COMSOL simulation model of piezoelectric generator is established to analyze the effects of flow velocity,cylindrical resistance fluid diameter and spacing ratio on the vortex shedding frequency.The output energy of the system can be further improved when the flow velocity is 10m/s and the spacing ratio is 1.9D.(3)Simulation of the fixed mode of piezoelectric vibrator in fluid-solid coupling shows that the fixed left end of piezoelectric vibrator can further improve the energy output of piezoelectric generator.Simulation of the output energy and dynamic response characteristics of piezoelectric vibrator and PVDF piezoelectric film in air and liquid can improve the output energy of piezoelectric generator by increasing the air flow rate.The output energy of the piezoelectric generator decreases with the increase of liquid velocity,which indicates that vortex-induced resonance occurs.Due to the frequency locking effect of vortex-induced vibration,the frequency of the piezoelectric generator is locked near the natural frequency.(4)A test prototype of a piezoelectric generator was designed and made,and a test system of a piezoelectric generator with vortex-induced vibration was built to explore the output energy of the piezoelectric generator under different resistance fluid diameter and flow rate.The experiment showed that the piezoelectric generator could output 2.1V at 20mm,and the experimental test results were basically consistent with the simulation results.The ltc3588-1 weak energy collection chip of Lintel is used to charge the storage capacitor at one end of the chip by vibrating the piezoelectric vibrator after wind speed excitation.The experiment shows that after 75s,the voltage is increased from 0V to 1.5V by using the piezoelectric vibrator to charge both ends of the storage capacitor,and the energy storage capacitor voltage can be used as an external power supply to power the load.After 108s,PVDF piezoelectric film is used to charge both ends of the storage capacitor,and the voltage increases from 0V to 0.63V.Compared with the piezoelectric vibrator,the charging effect of PVDF for the storage capacitor is poor,which indicates that the use of piezoelectric vibrator as the core device of the piezoelectric generator with vorticity-induced vibration has certain practical value. |
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