Design And Research Of The Piezoelectric Pump With Compressible Spaces

With the development of science and technology,the demand for output performance of piezoelectric pump is increasing.It is urgent to improve the output performance of piezoelectric pump under constant volume and power consumption.At present,the main effect of the piezoelectric pump performance factors: firstly,the traditional one-way valve has a serious lag,resulting in the performance of piezoelectric pump in high frequency condition is poor,and it do not play the piezoelectric materials with high energy density advantage;secondly,due to the characteristics of the liquid do not be compressed,resulting in piezoelectric pump inlet and outlet pressure load the higher,and the traditional piezoelectric pump without load buffer structure,to reduce the load.For question two,based on the traditional structure of piezoelectric pump,this paper makes improvement: put forward a kind of a compression chamber piezoelectric pump,its structure is improved mainly in the lower part of the external space pump,entrance valve two additional elastic diaphragm with compressible space in the pump process compressible space structure reduces the driving load of the piezoelectric vibrator,the fluid flow plays a smooth transition function,improve the output flow of the piezoelectric pump in single cycle.The overall content is as follows:In this paper,the PZT5 piezoelectric ceramic is used as the driving element for the piezoelectric pump of the compressible space.The rectangular wave with large energy density is used as the signal to drive the piezoelectric pump.The limit output pressure and the limit output flow of the piezoelectric pump are discussed.Theoretical analysis shows that the main factors affecting the piezoelectric oscillator are the structure of the oscillator,the support mode,the life span and the material of the ceramic and metal substrates,and when these are determined,the displacement of the piezoelectric oscillator is only related to its driving voltage.Therefore,the piezoelectric pump driving voltage is certain,can determine the performance of the piezoelectric pump.The influence of the height of the piezoelectric pump on its self-priming performance and output performance is discussed from the angle of compression ratio,and the flow of the prototype is optimized when the space height is 0.15 mm.The effect of the reverse cut-off of the wheel valve and the reverse leakage on the performance of the piezoelectric pump is analyzed,and the process of the valve plate preparation is improved.The stiffness of the wheel type valve is deduced and three kinds of different cantilever lengths are designed to simulate and test the stiffness.The modal simulation analysis is carried out so as to analyze how the stiffness of the valve plate affects the performance of piezoelectric pump with compressible space.The head loss caused by fluid movement in the pipeline of the piezoelectric pump is described,and the head loss and local head loss are divided according to the different manifestations.Combining the fluid-solid coupling simulation with the flow characteristics and head loss theory of the piezoelectric pump,the influence mechanism of the compressible space height and the thickness of the elastic diaphragm on the flow of the fluid in the compressible space is explained.The experimental prototype of the compressible space piezoelectric pump is produced and compared with the performance test results,the output flow of the piezoelectric pump with compressible space is increased by about 30% compared with the traditional structure piezoelectric pump.By changing the height of the compressible chamber and the thickness of the elastic diaphragm,the trend is in agreement with the simulation result: the output performance of the prototype can be decreased when the height of the compressible space increases and the thickness of the elastic diaphragm increases.In this paper,the structure of piezoelectric pump is improved with the knowledge of piezoelectricity,fluid mechanics,material dynamics,elasticity,mechanical vibration and so on,and a piezoelectric pump structure with compressible space is proposed,and the compressible space is analyzed and discussed by means of theory,simulation and experiment.It lays a technical foundation for the improvement of the subsequent piezoelectric pump structure.It provides a reference for the improvement of similar fluid conveying equipment.