The Research On Piezoelectric Pump With Active Valve Actuated By Rectangular Piezoelectric Wafer

In this thesis,the research and progress of the piezoelectric pump both at home and abroad were Summaried.By comparing the principle of piezoelectric pump with passive and active valve,this thesis proposed the potential value of piezoelectric pump with active valve.Funded by National Science Foundation of China (No.50575093),this thesis focused on developing piezoelectric pump with active valve.The basic theory,structural design and experimental test were analyzed and carried out in this thesis.The main content of this dissertation is as bellows:1.Introduction of piezoelectric pump with active valve This paper introducted the classification and development of micro-pump and piezo-pump at home and abroad.By comparing the piezoelectric pump and micropump driven by other forms,this paper described the merits of a series of piezoelectric pumps,based on their own unique characteristics,they werealready widely used in biological gene,chemical analysis,aero and space areas.However,from an experimental prototype to a reliable,easy to use products,there still exists many difficulties,therefore,the piezoelectric pump requires further research work.2.The basic theory of piezoelectric materialThe basic concept of the piezoelectric effect,the basic physical properties of the piezoelectric material and the important performance parameters,four kinds of piezoelectric equations were introduced.The vibration modes,the equivalent circuit resonance characteristics were analyzed.The theory on the basis of piezoelectric actuators was expounded,which provides the theoretical references to the design of piezoelectric pump and active valve driven by piezoelectric actuator. 3.The research on the characteristics of the piezoelectric cantilever beam actuated active valveIn this paper,the piezoelectric bimorph was selected as actuated element ofactive valve after a comprehensive analysis of the driving approach of various micro-valves.This paper introduced various supporting ways and electricalconnections of the piezoelectric cantilever beam,based on the support of different ways, two active valves were designed.Theoretical analysis and experimental research on the key component of this active valve piezoelectric double-wafer were carried out,the static and dynamic characteristics of rectangular piezoelectric bimorph actuator were simulated by FEM,they were also measured and analyzed through experimental test;the deformation law and factors which have influences on the flow were analyzed.Based on the flow formula,factors affecting the flow was analyzed;the structural of the active valve wasoptimized.4.The structural design and theoretical analysis of the piezoelectric pump with active valveAccording to the working principle of piezoelectric pump with active valve,the pressure distribution inside the chamber was analyzed.The theoretical output flow formula of piezoelectric pump was derived,the theoretical output flow was also calculated.All things above supply the theoretical references to the design of piezoelectric pump.5.Design of piezoelectric pump with active valveBased on the gripping ends,the piezoelectric pump with active valve actuated by rectangular piezoelectric wafer was designed,the best phase between the valve cavity and piezoelectric oscillator cavity piezoelectric wafer was drawed.The output characteristics of it was measured,the factors which affect the performance of pump,such as phase voltage,frequency,phase,and drive signal were analyzed.The bi-directional pumping capacity was also compared.At last,the difference between the actual flow and the theoretical flow was analyzed.