Research On Optimal Structure Of Piezoelectric Micropump Based On Microfluidic System

The piezoelectric micropump is an important part of the microfluidic system and determines the stability and reliability of the microfluidic system.It is a micropump with excellent performance that is produced with the constant innovation and development of various materials and structures.The utility model has the advantages of simple structure design,small volume,easy carrying,good conveying performance,accurate control and the like.Among them,the piezoelectric vibrator,the valve body,the pump body material and the structure composition have an extremely important influence on the output performance of the piezoelectric micropump.This article focuses on the optimization of the micro-pump structure,mainly in the following aspects:1)Study deduced the deflection equation of the piezoelectric vibrator,the volumetric equation of the volume of the pump chamber,and the transmission performance equation,and verified the accuracy of the theory through simulation.The substrate material and diameter ratio of the piezoelectric vibrator were selected.The thickness was optimized for the structure.2)Three kinds of valve body structures,namely cantilever type valve body,wheel type valve body and umbrella type valve body,are designed,and the deflection equation in the vibration process and the flow equation of the micro pump are deduced,and ANSYS simulation software is used.The valve body has been structurally optimized.A single-cavity and dual-cavity piezoelectric micro-pump was designed by combining the optimized piezoelectric vibrator and valve body,and the theoretical flow rate equation of the micro-pump was deduced,and the thickness and diameter of the valve body and the pump body were optimized through experiments.The pump cavity height,inlet and outlet diameter,valve hole diameter,boss height and other structural parameters,developed a piezoelectric micro-pump with optimized structure.3)After an experimental study of a single-cavity and dual-chamber piezoelectric micro-pump,the maximum outlet pressure of the water delivered by a single-cavity piezoelectric micropump under the condition that a 50V sinusoidal voltage is applied to the micropump after the structure has been optimized And the delivery flow rates are 6.91 kPa and 4.27 ml·min-1,respectively;the maximum outlet pressure and delivery flow of the dual-chamber series piezoelectric micropump delivery water are 11.87 kPa and 6.04 ml-min-1,respectively;the dual-chamber parallel-type piezoelectric micropump delivery The maximum outlet pressure and delivery flow when water is driven asynchronously are 11.8 kPa and 5.84 ml-min-1,respectively.4)Using Fluent simulation software to simulate water,glucose solution and ethylene glycol solution,it can be seen that the three fluid media will have a large flow loss in the pump,and the greater the viscosity,the greater the flow loss.The single-chamber and double-chamber piezo-electric micropumps were used to carry out experiments on the mixed liquors with different viscosities of glycerol and water.After experiments,it was found that the delivery flow will continuously decrease with the increasing viscosity of the mixed liquid,and the largest The frequency corresponding to the delivery flow will also continue to decrease.When the viscosity of the mixed solution is large,the flow rate of the micro-pump is very small,and when the frequency is increased,the flow rate of the micro-pump is hardly changed.