Electro-solid-fluid Coupling Simulation And Dynamic Modeling Of Valveless Piezoelectric Micropump

As an important power source in the microfluidic system,the valveless piezoelectric micropump is driven by the reverse piezoelectric effect to form the reciprocating motion of fluid in the pump cavity,and the directional transport of the fluid is realized through a special channel.It has a broad application prospect in many fields.At present,the development of valveless piezoelectric micropump mainly focuses on the driving mechanism and processing method,while the traditional experimental research can not predict the output characteristics in advance,besides,it is hard to know the transient flow characteristics of the internal fluid in the micropump.In addition,the numerical simulation methods are mostly limited to single domain,and the coupling effect of multiphysical fields is not considered yet.In this paper,through theoretical modeling analysis,fully coupled numerical simulation and experimental method,the research on the valveless piezoelectric micropump involving the three field coupling of piezoelectric-solid-fluid mainly includes the following parts:Based on the theory of small deflection of thin plate of elastic mechanics,the dynamic modeling of a piezoelectric actuator with a simplified double layer structure is modeled,and its vibration displacement equation is derived,meanwhile,the displacement distribution along the radius direction is obtained.The electric-fluid-solid coupling simulation of piezoelectric actuator and modal analysis is carried out to obtain the first order natural frequency.The transient dynamic analysis of piezoelectric actuator shows that the displacement of the center point is sinusoidal with time,and the maximum displacement of the center point of the piezoelectric actuator with the driving frequency below 200 Hz is proportional to the voltage amplitude.The laser displacement measurement experiment of piezoelectric actuator is carried out to verify the accuracy of the dynamic model and the electro mechanical coupling simulation.Considering the micro fluid mechanics based on the piezoelectric solid fluid,theflow characteristics of the fluid in the diffuser / nozzle tube are analyzed.The dynamic model of the whole pump is established through the average velocity and the average displacement.The output characteristic equation and the vibration frequency of micropump with the diffuser /nozzle tube are deduced,which can reflect the working characteristics of the whole pump in an all-round way,and provide a new idea for multi field coupling modeling of valveless piezoelectric micropumps.Through multi physical field coupling analysis software COMSOL Multiphysics,a three-dimensional coupling simulation method of valveless piezoelectric micro pump is established,which includes the internal coupling and bidirectional fluid solid coupling of the piezoelectric actuators.A more comprehensive analysis of the service characteristics of the piezoelectric actuator and fluid flow characteristics under the coupling effect is presented,which provides an effective scheme for the optimization design of the valveless piezoelectric micropump.The experiment of valveless piezoelectric micropump with different diffusion angles is carried out.The experimental results show that the output flow rate of the micropump increases with the increase of the driving voltage,and valveless piezoelectric micropump under the condition of different structures corresponds to the different optimum working frequency,and the optimum operating frequency range is75-100 Hz for micropump tube when ratio of length and width=15 and the throat length =200 ?m.The best working frequency decreases with the increase of diffusion angle.The optimal diffusion angle is 10 degrees under the condition that the driving voltage range is 25-150 Hz and the amplitude range is 50-150 Vpp.