Mechanistic Study Of A Novel Integral Cantilever Valve Piezoelectric Pump Based On Flexible Elements

As piezoelectric pumps have certain fluid delivery capability to achieve precise delivery requirements and purposes,they are widely used in drug delivery and drug delivery systems,chip and chemical analysis systems,DNA hybridization and solution mixing,thermal management and electronic cooling,fuel cells,gas chromatography analysis,piezoelectric micro-injection equipment,nebulizers and other fields.Valved piezoelectric pumps have better output performance than valveless piezoelectric pumps because they can use valves to suppress the backflow phenomenon.In order to improve the performance of valved piezoelectric pumps,some researchers have adjusted the driving frequency of the piezoelectric actuator to make it resonate at the same frequency as the cavity,thus causing the whole piezoelectric pump system to resonate and increasing the amplitude of the check valve.But at present,the passive check valve piezoelectric pump for the existence of the valve is not easy to open,open small,high resistance and the optimal resonance frequency of the pump and other aspects of the problem,many researchers have not been studied in depth.Based on the structure and working principle of traditional cantilever valve,this paper designs a novel integral cantilever valve based on a flexible element.The inlet cantilever valve and the outlet cantilever valve of this valve are connected to the flexible element through the connecting column.Based on the structural characteristics of the integral cantilever valve,the semi-cylindrical seat is designed to facilitate its installation and its own characteristics.The theoretical comparison analysis of the two types of valves concluded that the improved integral cantilever valve based on the conventional type cantilever valve has the advantages of good shutoff,large opening and low forward energy loss,and the efficiency equation of the piezoelectric pump is derived.The effectiveness of the cantilever valve body and flexible components as well as the reliability of the rubber material are proved by the simulation analysis of the bi-directional fluid-solid coupling of the integral cantilever valve piezoelectric pump.The modal analysis and harmonic response analysis were also performed by combining different parameter values of the cantilever valve thickness H,the radius R of the effective flexible member and the length L of the connecting column of the integral cantilever valve.It was proved that the amplitude of the integral cantilever valve piezoelectric pump at 54Hz when the cantilever valve thickness H is 0.9mm,the radius R of the effective flexible member is4.5mm and the length L of the connecting column is 8.65mm can reach the maximum at54Hz,with a maximum of 0.0514μm.The static performance test setup and performance test system of the integral cantilever valve and the conventional cantilever valve were then built.When the thickness H of the cantilever valve is 0.7mm,the effective radius R of the flexible member is 4.5mm,and the length L of the connecting column is 8.65mm,the piezoelectric pump has better flow and back pressure performance performance at 40Hz,which is more suitable for the application and development research in the low frequency field.Finally,performance tests were conducted on the combination of various parameter values of the integral valve,and the results showed that the flow rate of the piezoelectric pump could reach 285ml/min under the conditions of driving voltage of 210Vrms,frequency of 65Hz,fluid of water,cantilever valve thickness H of 0.9mm,effective radius of flexible element R of 4.5mm,and connection column length L of 8.65mm.Under the same conditions,the frequency is 55Hz and the back pressure reaches the maximum value of 92.9cm H~2o.The structural design and study of a novel integral cantilever valve piezoelectric pump based on flexible components effectively proves the effectiveness and feasibility of the integral cantilever valve,and its output performance has better performance in the low frequency region.It provides a new idea for reducing the resonant frequency of piezoelectric pump.