Research On The Piezoelectric Pump With Bimorph Piezoelectric Vibrator Active Vavles

Piezoelectric pump of active vavles has the characteristic of fast response, high working frequency ,the ability of pump fluid bidirectionally etc.In recent years, the domestic and foreign related researchers have paid more attention on the new research area of the pizeoelectric pump. Funded by the National Natural Science Foundation Project (No.50575093), this thesis focused on developing piezoelectric pump with active valves. Designed and manufactured two kinds of pizeoelectric pumps which take bimorph piezoelectric vibrator as the actuator of active vavles.Analysed the working principle and working performances,then made experimental test which laid the foundation for the further research work.The main content of this dissertation is as bellows:1.Introduction of piezoelectric pump with active valveBased on the research and analysis on the current research work on micro pump and micro valve, this paper focused mainly on the current condition and development of piezoelectric pump with active valve. The principal achievements of the study on piezoelectric pump are piezoelectric pump with check valve, piezoelectric stack pump, piezoelectric pump without check valve and piezoelectric ultrasonic pump and they are already widely used in biological gene, chemical analysis, and aero and space areas. The piezoelectric pump with active valve was a new subject which was brought forward in recent years. Hence, understanding the working condition deeply and improving the performance of piezoelectric pump with active valve are new emphasis of the study on piezoelectric pump.2.Theory and Simulation of the bimorph piezoelectric vibratorIntroduced the basic physical characteristics of the piezoelectric material,including the basic concept of the piezoelectric effect, the polarization phenomenon of the piezoelectric material,the four vibration modes, the equivalent circuit resonance characteristics were analyzed. calculated the resonance frequencies and modes shape of bending model of structure are derived.Comparing the installations,the materials of substrate,the radius ratio of ceramic and substrate, thickness of the ceramic and substrate, By ANSYS optimized, we chose the proper structural parameters of piezoelectric vibrator,also analyzed the static and dynamic piezoelectric vibrator.3.Experimental research on the bimorph piezoelectric vibratorBuilt the experimental testing system of the bimorph piezoelectric vibrator, by testing the static and dynamic characteristics of piezoelectric vibrator and amplitude-frequency characteristics, researched on the influences of the piezoelectric vibrator for the different waves,different voltages,different frequencies.Compared the FEM results and experimental test results,found that they had identical trend,small error,the biggest error is about 20%. The experimental results testified the FEM model is meaningful for structure design.4.Design and experiment the active vavleDesigned and manufactured an active vavle based on the bimorph piezoelectric vibrator,confirmed the structure of active vavle,analysed its working principle. The active valve was constructed by bimorph piezoelectric vibrator. Deduced the theoretical flow, the height,diameters and width of the valve are known as the factors influencing the flow. When fluid passed a slit,there were not only the viscous pressure loss of the flow but also convective losses must be taken into account.we got the relation of the fluid pressure losses with the height,diameters and width of the valve by Ansys Flotran.Based on the theoretical flow as large as possible, and the fluid pressure losses as small as possible,we selected valve structure parameters finally.we tested the performances of the active vavle ,including leakage ,flow, pressure containing,which were good enough for the designing of the piezoelectric pump with active vavle.5.Design and experiment the two different structure active vavle pumpsResearched and manufactured two different active vavle pumps: piezoelectric pump with three chambers and two active vavles and peristaltic piezoelectric pump with active vavle. Analysed the working principle and working performances of two kinds of piezoelectric pumps with active vavles,and discussed actuation methods respectively.According to the requirements of piezoelectric pump on the drive signal, the test rig based on LABVIEW was built up. The rig has the functions of three channels output, signal type can be selected, adjustable amplitude, frequency, duty cycle and phase which can be satisfied the control demand of piezoelectric pump.Carried on experimental researches on two kinds of piezoelectric pump of active valves.Tested the piezoelectric pump's frequency-flow characteristic, the valve chamber vibrator's voltage-flow characteristic,the pump chamber vibrator's voltage-flow characteristic, and the back pressure-flow characteristic,etc.The test results indicated that the pizeoelectric pump with three chambers and two active vavles has the characteristic of wide working frequency domain (30～170Hz),forward and reverse fluid flow didn't exist obvious differences. Peristaltic pizeoelectric pump with active vavles has the stronger abilities of pump water and pressure containing.Moreover, piezoelectric pump of active vavles whose pump air ability was better than its pump water ability.Also,the piezoelectric pump has the ability of pump fluid bidirectionally.