Research On The Valveless Piezoelectric Pump With Dome Composite Structures

The piezoelectric pump is highly concerned in the pump fields because it has the precise control,no electromagnetic interference.The valveless piezoelectric pump not only has the above advantages,but also has a unique structure,no wear between the valve and the pump body,and low cost.So it is popular in the field of piezoelectric pumps,and it has broad application prospects in aerospace,precision mechanical lubrication and experimental field drip irrigation.However,the reflux phenomenon of the valveless piezoelectric pump limits its output performances severely,which has certain limitations in the practical application field of the valveless piezoelectric pump.In order to alleviate the reflux phenomenon of the valveless piezoelectric pump,the proper structure is arranged inside the cavity to decrease the pressure loss of the liquid flowing into the pump cavity in the inlet,increase the pressure loss of the liquid flowing into the pump cavity from the outlet pipe,and form a pressure difference between the positive and negative liquids,thereby improving the output performances of the valveless piezoelectric pump.The purpose of widening the valveless piezoelectric pump application field.This article will study the following main aspects:(1)Using the liquid to generate different pressure loss in the suction stroke and the discharge stroke,a valveless piezoelectric pump with a dome composite structure in the pump chamber is proposed.Based on the analysis of the vibration mode of the piezoelectric actuator,a reasonable mode shape is taken,and the(37)35 mm circular piezoelectric actuator is determined as the driving core component by analyzing the power drive source of the piezoelectric pump,which lay a foundation for the experimental analysis of the valveless piezoelectric pump.(2)The vibration model of the piezoelectric actuator is established.The maximum vibration variation of the piezoelectric actuator is derived theoretically.The pressure loss caused by the elements of the dome composite structures is analyzed.The derivation formula of output flow rate in the valveless piezoelectric pump is theoretically obtained.It provides guidance for the design of the valveless piezoelectric pump.(3)Using the simulation software ANSYS CFX to analyze the flow rate curve and pressure loss generated by the liquid inside the pump chamber.After simulation,the liquid have different flow velocity and pressure loss under different size dome structure,trapezoidal single-sided angle and rounded diversion structure.When the dome structure size is 6 mm,the trapezoidal single-sided angle is 5° and rounded diversion structure is 6 mm,the sum of the forward and reverse pressure losses reaches a minimum of 94.17 Pa.When the dome structure is 8 mm,the sum of the forward and reverse pressure losses is 94.62 Pa,which provides an effective reference value for the test of the piezoelectric pump.(4)According to the design scheme,a valveless piezoelectric pump with different dome structure,trapezoidal single-sided angle and rounded diversion structure parameters was fabricated,and an experimental platform was built for testing the pumps.The results show that the maximum output flow rate of the valveless piezoelectric pump is 220.6 ml/min,and the maximum output pressure reaches 670 Pa under the dome structure 8mm,the trapezoidal single-side angle 5° and the rounded diversion structure 6 mm.The pressure loss of the piezoelectric pump reaches the minimum state,and the output performances are optimal.The test results show the same tendency with the simulation results basically.In the structural stability measurement,the pump output flow rate variance under this parameter reaches 80.7,which fully meets the test requirements and the reliability of the structure is verified.