非对称分叉流管无阀压电泵的设计及试验

具有微混合功能的多级Y型流管无阀压电泵存在着输出流量与振子带载能力不平衡的问题。为此，提出了一种非对称分叉流管无阀压电泵。首先，理论分析了该无阀压电泵输出流量与流管流阻间的关系；其次，利用有限元软件数值计算了多级Y型流管的流阻特性；最后，采用光固化快速成型技术加工了样机，并进行了泵特性试验和振子振动测试。试验结果表明：在峰峰值200 V正弦波交流电驱动下，该压电泵的流量、扬程和压电振子的振幅都随驱动频率增加呈现先增大后减小的趋势；当驱动频率为31 Hz时，最大流量为4 g/min；驱动频率为38 Hz时，最大扬程为40.5 mmH2O。在试验施加电压范围内，该泵的输出性能与驱动电压呈正相关性。本研究验证了非对称流道树型无阀压电泵的可行性，为非对称无阀压电泵在微流道滴灌和微混合等领域的应用提供了参考。     

三棱柱阻流体无阀压电泵的设计与试验

以三棱柱阻流体为无移动部件阀,结合3D打印技术的快速一体成型特点,设计并制作了以压电振子为动力源的三棱柱阻流体无阀压电泵。分析了该无阀压电泵的工作原理、理论流量和振子振动特性,推导出了它的的流量表达式。利用有限元法对三棱柱阻流体的流阻特性进行了仿真模拟,由其内部压强分布及进出口流速情况,定性分析了三棱柱阻流体的正反向流阻大小。最后,使用3D打印机制作了该无阀泵的试验样机,并进行了流阻和流量测量试验。试验结果表明:三棱柱阻流体具有正反向绕流流阻不等的特性,当驱动电压为550V,驱动频率为8 Hz时,该压电泵的输出流量达到最大,为29.8mL/min。结果证明了该三棱柱阻流体无阀压电泵具有良好的输送流体的能力。     

A valveless piezoelectric pump with novel flow path design of function of rectification to improve energy efficiency

Existing valveless piezoelectric pumps are mostly based on the flow resistance mechanism to generate unidirectional fluid pumping, resulting in inefficient energy conversion because the majority of mechanical energy is consumed in terms of parasitic loss. In this paper, a novel tube structure composed of a Y-shaped tube and a ȹ-shaped tube was proposed considering theory of jet inertia and vortex dissipation for the first time to improve energy efficiency. After verifying its feasibility through the flow field simulation, the proposed tubes were integrated into a piezo-driven chamber, and a novel valveless piezoelectric pump with the function of rectification (NVPPFR) was reported. Unlike previous pumps, the reported pump directed the reflux fluid to another flow channel different from the pumping fluid, thus improving pumping efficiency. Then, mathematical modeling was established, including the kinetic analysis of vibrator, flow loss analysis of fluid, and pumping efficiency. Eventually, experiments were designed, and results showed that NVPPFR had the function of rectification and net pumping effect. The maximum flow rate reached 6.89 mL/min, and the pumping efficiency was up to 27%. The development of NVPPFR compensated for the inefficiency of traditional valveless piezoelectric pumps, broadening the application prospect in biomedicine and biology fields.     

Research on the valveless piezoelectric pump with Y-shape pipes

A piezoelectric pump with its Y-shape elements is presented. Two Y-shape pipes are fixed outside the chamber serving as an inlet and outlet, with the chamber and a piezoelectric vibrator being the actor. The pump has the potential to be miniaturized and integrated. Eddies occurring in the Y-shape elements are smaller, which is beneficial for the transport of living cells or long-link macromolecules. In this paper, the structure of the pump is first presented. Then, the equations on the change in volume and the mean pressure in the chamber are established, as well as the relation between the flow rate and the working frequency of the piezoelectric vibrator. Moreover, the relation between the mean pressure in the chamber and the working frequency of the piezoelectric vibrator is established. Finally, experiments are carried out to test the characteristics of the pump and to verify the correction of the theory on this pump.     

非对称坡面腔底无阀压电泵

提出了一种新型的非对称坡面腔底无阀压电泵,这种泵巧妙地利用了泵腔内部的空间,将泵腔底部沿吸入口和排出口方向设计成非对称坡面形状,非对称坡面腔底与压电振子之间形成非对称交替排列的一组锥形流道.当泵工作时,使流体产生单向流动,从而可以不再需要传统的锥形流管;建立了这种泵关于平均值的流阻系数与泵流量关系的力学模型,并利用该模型分析了泵的工作原理;最后制作了非对称坡面腔底无阀压电泵,利用试验证明了上述理论的正确性.试验用泵采用的工作电压为220 V,工作频率为50 Hz,压电振子有效直径为30 mm,当非对称坡面的倾角差为70°,工作介质为水时,泵产生了4.67 mm水柱的压差.     

一种仿生型无阀压电泵

针对传统的容积型流阻差式无阀压电泵具有吸入周期和排出周期,存在着流动脉动大、流量小的问题,提出一种新型的鱼鳍摆动式无阀压电泵。模仿在鱼类中巡游速度最快的金枪鱼的鱼体结构,设计了压电双晶片结构的压电振子,并将其尾鳍设计成柔性叶片状。分析了压电双晶片结构悬臂梁的受力变形、模态振型在机电转换效率方面的关系。研制了泵的样机并测量了激励电压在100 V时泵的流量。实验结果表明:振子工作在1阶振型时,泵水效应不明显;振子工作在2阶振型时,谐振频率为740 Hz,泵的流量为266 mL/min;振子工作在3阶振型时,谐振频率为1 280 Hz,泵的流量为105 mL/min。     

压电振子及流体对泵近场噪声的影响

研究了压电振子的弯曲振动形变及振动辐射噪声.首先建立压电泵压电振子振动方程,导出弯曲振动形变函数;提出用微平面活塞振动理论简化压电振子振动模型,推导了近场声压理论计算方程及泵内流体对泵噪声贡献量方程;最后把理论计算结果与试验结果进行比较分析,分别得出在不同频率下压电振子及泵内流体对泵噪声贡献的大小.在输入频率为50 Hz时,泵噪声的理论值为45 dB,实际值为37 dB,泵内流体对泵噪声的影响较大,实际值与理论值的相对误差为21.6%;在输入频率为120 Hz时,泵噪声的理论值为61 dB,实际值为62 dB,泵内流体对泵噪声的影响较小,实际值与理论值的相对误差为1.6%,证明了本研究所提出理论的正确性.     

Theory and experimental verification on valveless piezoelectric pump with multistage Y-shape treelike bifurcate tubes

Among most traditional piezo water cooling systems, piezoelectric valve pumps are adopted as their driving sources. The valves in these pumps induce problems of shock and vibration and also make their structure complicated, which is uneasy to minimize and reduce their reliability and applicability of the whole system. In order to avoid these problems caused by valve structure, a novel valveless piezoelectric pump is developed, which integrates both functions of transforming and cooling. The pump’s Y-shape tree-like construction not only increases the efficiency of cooling but also the system reliability and applicability. Firstly, a multistage Y-shape treelike bifurcate tube is proposed, then a valveless piezoelectric pump with multistage Y-shape treelike bifurcate tubes is designed and its working principle is analyzed. Then, the theoretical analysis of flow resistance characteristics and the flow rate of the valveless piezoelectric pump are performed. Meanwhile, commercial software CFX is employed to perform the numerical simulation for the pump. Finally, this valveless piezoelectric pump is fabricated, the relationship between the flow rates and driving frequency, as well as the relationship between the back pressure and the driving frequency are experimentally investigated. The experimental results show that the maximum flow rate is 35.6 mL/min under 100 V peak-to-peak voltage (10.3 Hz) power supply, and the maximum back pressure is 55 mm H2O under 100 V (9 Hz) power supply, which validates the feasibility of the valveless piezoelectric pump with multistage Y-shape treelike bifurcate tubes. The proposed research provides certain references for the design of valveless piezoelectric pump and improves the reliability of piezo water cooling systems.     

单振子双腔体无阀压电泵结构设计与机理分析

提出了一种单振子双腔体无阀压电泵,应用小挠度弹性弯曲理论导出了圆形复合压电振子的弹性曲面微分方程,分析了采用一个压电振子形成两个工作腔体压电泵的结构和工作机理,并与单振子单腔体压电泵对比分析了该结构与输出流量的关系。设计研制了结构独特、输出性能更高的单振子双腔体无阀压电泵,通过试验表明:单振子双腔体无阀压电泵比单振子单腔体无阀压电泵输出流量有明显提高。     

半柔性阀压电泵理论与实验

根据静脉瓣结构形式,设计了一种半柔性阀压电泵。首先,介绍了半柔性阀压电泵的结构及工作原理;其次,对阀体进行了理论分析;最后,加工了实验样机,对样机进行性能测试实验。实验结果表明:在驱动电压为220V、频率为7Hz时,半柔性阀压电泵的进出口压差可达到199mm;在驱动电压为220V、频率为11Hz时,半柔性阀压电泵的实验流量为44.5ml/min。随着驱动电压的升高,工作频率与流量出现单峰与双峰的现象。该研究证明了半柔性阀压电泵具有泵的功能并可以实现有阀和无阀状态,验证了其有效性和理论分析的正确性。     

3D打印的锥管坡面腔底无阀压电泵

为提高无阀压电泵的流量特性和解决泵加工工艺性差的问题,研制出了锥形流管坡面腔底无阀泵。首先,提出并设计了锥形流管坡面腔底无阀泵,分析了该泵的工作原理;然后,利用ansys软件对泵腔内流场做了模拟分析,分析结果表明该泵具有传输流体的能力;最后,利用3D打印技术制作了锥形流管坡面腔底无阀泵,并对泵的频率-流量特性进行了试验,驱动频率为8Hz时,锥形流管坡面腔底无阀泵的流量达到最大值26.8ml/min,比相同尺寸坡面腔底无阀压电泵在相同驱动电压条件下输出的最大流量增加了18.6%。试验结果表明,锥形流管坡面腔底无阀泵的流量特性优于坡面腔底无阀压电泵,且采用3D打印技术制作压电泵,提高了泵加工的工艺性,缩短了加工周期,降低了加工成本。     

多级“Y”型流管无阀压电泵的原理与试验验证(实验视频)

针对目前微流体混合器多需要外接动力源,且多数微混合器只能进行液体混合而不能输送液体的问题,提出将无阀压电泵引入微混合器领域,并研制了一种集混合与输送于一体的多级“Y”型流管无阀压电泵。首先,提出了多级“Y”型流管,进而设计了多级“Y”型流管无阀压电泵,并分析其工作原理;然后,对该无阀压电泵的流管流阻特性及泵流量进行理论分析;同时,利用有限元软件对多级“Y”型流管无阀压电泵进行了流场模拟,结果表明该压电泵具有单向传输作用。最后,制作了多级“Y”型流管无阀压电泵样机,并进行了泵流量与背压试验。试验结果显示：驱动电压峰峰值为100 V,频率为16 Hz时,流量达到最大,为16.2 ml/min;驱动电压峰峰值为100 V,频率为14 Hz时,输出背压最大,约为64 mm水柱。得到的试验数据证明了多级“Y”型流管无阀压电泵的有效性。(实验视频)     

3D FEM analyses on flow field characteristics of the valveless piezoelectric pump

Due to the special transportation and heat transfer characteristics, the fractal-like Y-shape branching tube is used in valveless piezoelectric pumps as a no-moving-part valve. However, there have been little analyses on the flow resistance of the valveless piezoelectric pump, which is critical to the performance of the valveless piezoelectric pump with fractal-like Y-shape branching tubes. Flow field of the piezoelectric pump is analyzed by the finite element method, and the pattern of the velocity streamlines is revealed, which can well explain the difference of total flow resistances of the piezoelectric pump. Besides, simplified numerical method is employed to calculate the export flow rate of piezoelectric pump, and the flow field of the piezoelectric pump is presented. The FEM computation shows that the maximum flow rate is 16.4 mL/min. Compared with experimental result, the difference between them is just 55.5%, which verifies the FEM method. The reasons of the difference between dividing and merging flow resistance of the valveless piezoelectric pump with fractal-like Y-shape branching tubes are also investigated in this method. The proposed research provides the instruction to design of novel piezoelectric pump and a rapid method to analyse the pump flow rate.     

Analysis of the flow rate characteristics of valveless piezoelectric pump with fractal-like Y-shape branching tubes

Microchannel heat sink with high heat transfer coefficients has been extensively investigated due to its wide application prospective in electronic cooling. However, this cooling system requires a separate pump to drive the fluid transfer, which is uneasy to minimize and reduces their reliability and applicability of the whole system. In order to avoid these problems, valveless piezoelectric pump with fractal-like Y-shape branching tubes is proposed. Fractal-like Y-shape branching tube used in microchannel heat sinks is exploited as no-moving-part valve of the valveless piezoelectric pump. In order to obtain flow characteristics of the pump, the relationship between tube structure and flow rate of the pump is studied. Specifically, the flow resistances of fractal-like Y-shape branching tubes and flow rate of the pump are analyzed by using fractal theory. Then, finite element software is employed to simulate the flow field of the tube, and the relationships between pressure drop and flow rate along merging and dividing flows are obtained. Finally, valveless piezoelectric pumps with fractal-like Y-shape branching tubes with different fractal dimensions of diameter distribution are fabricated, and flow rate experiment is conducted. The experimental results show that the flow rate of the pump increases with the rise of fractal dimension of the tube diameter. When fractal dimension is 3, the maximum flow rate of the valveless pump is 29.16 mL/min under 100 V peak to peak （13 Hz） power supply, which reveals the relationship between flow rate and fractal dimensions of tube diameter distribution. This paper investigates the flow characteristics of valveless piezoelectric pump with fractal-like Y-shape branching tubes, which provides certain references for valveless piezoelectric pump with fractal-like Y-shape branching tubes in application on electronic chip cooling.     

"Y"形流管无阀压电泵振动分析及泵流量计算

为了解决医疗、卫生、保健领域进行细胞或高分子等输送工作的需要,研制了一种新型的压电泵——"Y"形流管无阀压电泵,并对其压电振子振动特性及泵流量计算进行了研究。介绍了"Y"形流管无阀压电泵及其流管的结构和特点;基于圆形薄板弯曲振动理论对压电振子振动进行了理论分析;然后讨论了泵及其流管内流体的流动特性,建立了泵流量方程。最后,基于有限元法对流管内流体流动状态进行了模拟,得到了正反流压强变化规律及正反流流阻。实验结果表明:理论泵流量与实验泵流量变化趋势一致,且两者最小相对误差为12%,证明了理论分析与数值模拟的有效性和正确性。     

Analysis on flow field of the valveless piezoelectric pump with two inlets and one outlet and a rotating unsymmetrical slopes element

Typically,liquid pump and liquids mixer are two separate devices.The invention of piezoelectric pump makes it possible to integrate the two devices.Hower,the existing piezoelectric mixing-pumps are larger because the need the space outside the chamber,and another shortcome of them is that they cannot adjust the mixing ratio of two liquids.In this paper,a new piezoelectric pump being capable of integrating mixer and pump is presented,based on the theory of the piezoelectric pump with the unsymmetrical slopes element(USE).Besides the features of two inlets and one outlet,the piezoelectric pump has a rotatable unsymmetrical slopes element(RUSE).When the pump works,two fluids flow into the inlet channels respectively.Then the RUSE controls the ratio of the two flows by adjusting the flow resistances of the two inlet channels.The fluids form a net flow due to the USE principle,while they are mixed into a homogeneous solution due to strong turbulence flow field and complex vortices generated by RUSE in the chamber.And then the solution flows through the outlet.Firstly,the theoretical analysis on this pump is performed.Meanwhile,the flow field in the chamber is calculated and simulated.And then,the relationship between the flows of the two channels and the rotating angle of the RUSE is set up and analyzed.Finally,experiment with the proposed pump is carried out to verify the numerical results.A RUSE with 20° slope angle is used in the experiment.Four sets of data are tested with the RUSE at the rotating angles of 0°,6°,11°,and 16°,respectively,corresponding to the numerical models.The experimental results show that the empirical data and the theoretical data share the same trend.The maximum error between the theoretical flow and the experimental flow is 11.14%,and the maximum error between the theoretical flow ratio of the two inlets and the experimental one is 2.5%.The experiment verified the theoretical analysis.The proposed research provides a new idea for integration of micro liquids mixer and micro liquids pump.     

Simulation analysis and experimental verification of spiral-tube-type valveless piezoelectric pump with gyroscopic effect

The current research of the valveless piezoelectric pump focuses on increasing the flow rate and pressure differential. Compared with the valve piezoelectric pump, the valveless one has excellent performances in simple structure, low cost, and easy miniaturization. So, their important development trend is the mitigation of their weakness, and the multi-function integration. The flow in a spiral tube element is sensitive to the element attitude caused by the Coriolis force, and that a valveless piezoelectric pump is designed by applying this phenomenon. The pump has gyroscopic effect, and has both the actuator function of fluid transfer and the sensor function, which can obtain the angular velocity when its attitude changes. First, the present paper analyzes the flow characteristics in the tube, obtains the calculation formula for the pump flow, and identifies the relationship between pump attitude and flow, which clarifies the impact of flow and driving voltage, frequency, spiral line type and element attitude, and verifies the gyroscopic effect of the pump. Then, the finite element simulation is used to verify the theory. Finally, a pump is fabricated for experimental testing of the relationship between pump attitude and pressure differential. Experimental results show that when Archimedes spiral θ=4π is selected for the tube design, and the rotation speed of the plate is 70 r/min, the pressure differential is 88.2 Pa, which is 1.5 times that of 0 r/min rotation speed. The spiral-tube-type valveless piezoelectric pump proposed can turn the element attitude into a form of pressure output, which is important for the multi-function integration of the valveless piezoelectric pump and for the development of civil gyroscope in the future.     

轴向出流的单腔压电泵结构设计与性能研究

为提高压电泵的输出性能,设计了一种新型轴向出流的单腔有阀压电泵。泵体结构主要由3部分构成,即固定压电振子的上盖、带有腔体结构和被动截止阀的中间体及起压紧和密封作用的下盖。轴向出流的单腔压电泵的结构是将进口阀安装在圆柱形腔体的中心位置,保证进口管的轴线与压电振子垂直,出口阀安装在泵腔外,通过导流槽与泵腔连接,形成轴向进出流方式。将轴向出流的单腔压电泵和早期设计的侧向出流压电泵进行输出性能测试,试验发现,在低频工作阶段,侧向出流的单腔压电泵输出效果要略高于轴向出流,在高频工作阶段,后者要高于前者,而在整个40~400 Hz测试范围内,后者输出的液体压力都要高于前者。     

Multi-Field Analysis and Experimental Verification on Piezoelectric Valve-Less Pumps Actuated by Centrifugal Force

A piezoelectric centrifugal pump was developed previously to overcome the low frequency responses of piezoelectric pumps with check valves and liquid reflux of conventional valveless piezoelectric pumps. However, the electro-mechanical-fluidic analysis on this pump has not been done. Therefore, multi-field analysis and experimental verification on piezoelectrically actuated centrifugal valveless pumps are conducted for liquid transport applications. The valveless pump consists of two piezoelectric sheets and a metal tube with piezoelectric elements pushing the metal tube to swing at the first bending resonant frequency. The centrifugal force generated by the swinging motion will force the liquid out of the metal tube. The governing equations for the solid and fluid domains are established, and the coupling relations of the mechanical,electrical and fluid fields are described. The bending resonant frequency and bending mode in solid domain are discussed, and the liquid flow rate, velocity profile, and gauge pressure are investigated in fluid domain. The working frequency and flow rate concerning different components sizes are analyzed and verified through experiments to guide the pump design. A fabricated prototype with an outer diameter of 2.2 mm and a length of80 mm produced the largest flow rate of 13.8 m L/min at backpressure of 0.8 k Pa with driving voltage of 80 Vpp. Bysolving the electro-mechanical-fluidic coupling problem,the model developed can provide theoretical guidance on the optimization of centrifugal valveless pump characters.     

无阀压电泵的流固耦合仿真及试验验证

提出利用结构分析软件ANSYS和流体分析软件ANSYS CFX对无阀压电泵进行流固耦合仿真分析,以研究无阀压电泵的输出性能。分别对进口在中间出口在一侧、出口在中间进口在一侧、进出口对称布置的3种不同结构形式的无阀压电泵进行了流固耦合仿真分析。结果显示,上述3种无阀压电泵中,出口在中间进口在一侧结构形式的无阀压电泵的宏观输出流量最大。制作了3种无阀压电泵的试验样机,并搭建了相应的试验测试系统,在幅值为45 V、频率为0~700Hz的正弦信号激励下对其输出流量进行了测试。结果表明,3种不同结构形式的无阀压电泵的最大输出流量分别为3.8、6.0和4.0ml/min,出口在中间进口在一侧的压电泵输出流量最大,与流固耦合仿真分析的结果相吻合,验证了本文提出的流固耦合仿真分析的方法可以指导压电泵的设计。