Structural-fluid Coupling Simulation And Experimental Research On Piezoelectric Pump

Piezoelectric pump is a new type of fluid driving apparatus, which makes use of theconverse piezoelectric effect of piezoelectric ceramicsis to let the piezoelectric oscillatorvibrate up and down and then generate the volume change of the pump chamber. Comparedwith the traditional pump, piezoelectric pump combines the driving source part, transmissionpart and the pump body into one, possessing the advantages of small volume, simplestructure, low energy consumption and so on. Driven by the sinusoidal ac signal with acertain amplitude and frequency, piezoelectric pump can achieve precise control of outputflow and has broad application prospects in the aerospace, robotics, automotive, medicaldevices, bio-genetic engineering, micro-mechanical and other fields. Currently, domestic andoverseas analysis on the interaction of the piezoelectric vibrator and the fluid in the pump israre, therefore, this paper presents the structural-fluid coupling simulation on the valvelesspiezoelectric pump, researching flow patterns and velocity distribution of water in thepiezoelectric pump under the structural-fluid coupling state. The main work of this article isas follows:1. The research status of piezoelectric pumpAccording to the simulation status of piezoelectric pump at home and abroad, theresearch status and application fields of piezoelectric pump are analyzed and thestructural-fluid coupling simulation on the valveless piezoelectric pump is proposed basedon the ANSYS software and CFX software in this paper. This kind of simulation not onlycan solve flow field changes caused by the deformation of the piezoelectric oscillator, butalso can solve the deformation of the piezoelectric oscillator due to the reaction forcegenerated by the deformed flow field. Therefore, it analyses the entire process about theinteraction between the piezoelectric oscillator and the fluid, which not only can saveanalysis time and cost effectively but also can ensure that the simulation results are moreclose to the flow law of piezoelectric oscillator.2. Analysis on piezoelectric basic theory and structural-fluid coupling basic theoryPZT material with the vibration mode LE is selected as the drive element of thepiezoelectric pump in this paper, which is supported simply. In order to derive therelationship between the driving voltage and the sensing voltage of piezoelectric vibrator, thedynamic model of the circle bimorph piezoelectric vibrator is established and its self-sensingfeatures are analyzed from the two aspects of working principle and mathematical theory.Through studying the theoretical knowledge of the structural-fluid coupling, the separation solution and MFX multi-field solver are chose to solve the bi-structure-fluid interaction ofthe valveless pump, then two kinds of data interpolation methods that MFX provides arecompared and finally the conservative interpolation method is selected to achieve the precisedelivery of date between piezoelectric vibrator and fluid region.3. Simulation on the valveless piezoelectric pump with different distributed inlet/outletThe different distribution location of inlet/outlet has an influence on the piezoelectricpump’s output performance, in order to study the influence, the structural features andworking principle of three kinds of valveless pump are analyzed. These three kinds of pumpare the pump with middle inlet, the pump with middle outlet and the pump with sideinlet/outlet, respectively. The three-dimensional geometric models of piezoelectric vibratorand fluid region are established by means of ANSYS software. In this paper, a series of finiteelement analysis of piezoelectric vibrator is made, then the analog type, boundary conditions,initial conditions and other attributes of the fluid region are set up in the CFX software. Onthis basis, the structural-fluid coupling simulation on those three kinds of valvelesspiezoelectric pump is made and the results show that the output flow of the pump withmiddle outlet is maximum.4. The experimental analysis of the pump with different distributed inlet/outletThe prototype of the piezoelectric pump is designed and the test system for the pump isset up. The experimental results are as follows:Under the45V sinusoidal AC excitation signal, for the valveless pump with middleinlet, the valveless pump with middle outlet and the valveless pump with side inlet/outlet,they all drain water out from0Hz to13Hz and reach the maximum output flow rate at10Hz.The maximum output flow rate is3.8ml/min、6.0ml/min and4.0ml/min, respectively.Therefore, the output flow rate of the valveless pump that has the middle outlet is maximum,which is consistent with the results of the structural-fluid coupling simulation.Under the45V sinusoidal AC excitation signal, for the valved pump with middle inlet,the valved pump with middle outlet and the valved pump with side inlet/outlet, themaximum output flow rate can reach up to37.0ml/min、41.1ml/min and39.8ml/minrespectively and these maximum output flow are all obtained at10Hz, which proves theresults of the structural-fluid coupling simulation.