Theoretical And Experimental Research On Resonantly Driven Piezoelectric Pump

Piezoelectric pump, using the converse piezoelectric effect of piezoelectric crystals, is a new type of a fluidic device.With many merits such as simple structure, small volume, no electromagnetic interference, easy control and low driving power,therefore,the piezoelectric pump has extensive application prospects in the fields of chemical analysis, medical treatment, bioengineering and the fuel supply of engine etc.At present, piezoelectric pump has made considerable progress, which meet certain requirements in the output flow, pressure, and precision.But in the case of other requirement such as the transmission of gas and large viscosity of the fluid, the performance of piezoelectric pump is also poor and the application are more limited. The reason is that piezoelectric resonators overheat,leading to premature failure, and low output capacities when pumping gas and poor output performance when pumping big viscosity fluid. Thus, this paper proposes a way to construct resonantly driven piezoelectric pump,which works in the resonant enlarging mode.After studying, we can know that the pump has a large cavity volume variation and compression rate which can solve the problem of the traditional piezoelectric pump.This paper puts forward a form of chip ring piezoelectric resonators as the excitation source, which provide power for the piezoelectric pump in the form of vibration exciter, with the plunger type diaphragm and one-direction valve, they construct the resonantly driven piezoelectric pump. Executive the systematic study through theoretical analysis and experimental testing methods on the resonantly driven piezoelectric pump.Comprehensively analyses the change of the deflection of piezoelectric resonators, the resonance frequency and vibration amplitude ratio of vibration exciter, the deflection of diaphragm and the output flow of resonantly driven piezoelectric pump.On this basis, through the orthogonal experiment method, the structure parameters of the system are optimized, and tested the relationship between voltage, frequency with the output flow of resonantly driven piezoelectric pump, which provides theoretical basis to design resonantly driven piezoelectric pump with high-performance.Piezoelectric resonators is the driving element of the resonantly driven piezoelectric pump which is also the core componet. In this paper, we get the deflection of the piezoelectric resonators under the condition of fixed supporting boundary by using analytical method. On this basis, through the tests we get the influence relations between the deflection of the piezoelectric resonators with the driving signal. We get the method to choose structural parameters of piezoelectric resonators.Vibration exciter constituted by the piezoelectric resonators and the spring mass system is the resonate piezoelectric pumps'power components, the driven vibration displacement and output force will directly active to the diaphragm to drive fluid. This paper firstly establishes the working principle of the vibration exciter and establishes the vibration mechanics model. Based on vibration analysis principle, plate and shell theory we solve the resonant frequency, vibration amplitude ratio. Through numerical analysis and experiment, we get the relationship between the structural parameters of vibration exciter with the resonate frequence, vibration amplitude ratio and vibration displacement.The body of the piezoelectric pump is the part of the resonantly driven piezoelectric pump which directly act on fluid. As to the body of the piezoelectric pump, we establish the diaphragm's vibration model and analyze the influence law between diaphragm diameter,rigid discs diameter with vibration deflection and the output flow of the resonantly driven piezoelectric pump. We discussed the influence relationship between check valve, the height of cavity, cavitation with the output flow of resonantly driven piezoelectric pump.Tested by experiments on the relationship between structural parameters with the output flow of the piezoelectric pump, which provides theoretical basis to design resonantly driven piezoelectric pump.To further understand the structural parameters' influnce on the pumping performance, we did the orthogonal experiment of 4 factors and 3 levels on resonantly driven piezoelectric pump and analyse the experiment result by range method. To achieve the goal of maximum output flow rate, we obtained primary-secondary of factors and the best combination of levels of resonantly driven piezoelectric pump. Under the optimal combination, we also test the relationship between the output flow of resonantly driven piezoelectric pump with the frequency and voltage. The results show that resonantly driven piezoelectric pump demonstrates excellent performance when pumping gas.