流线形流管无阀压电泵的仿真与实验

基于现有无阀压电泵输送活体细胞或者长链功能性高分子时依然存在输送破坏与缠绕失性等缺点,提出了一种流线形流管无阀压电泵,研究了4组不同角度的流线形流管无阀压电泵的输出性能.首先,阐述了泵的结构及工作原理,建立泵的流量表达式;其次,采用Fluent流体分析软件对β角度分别为10°,15°,20°和25°的流管组成的无阀压电...     

无阀气体压电泵仿真分析与实验

为了提高微型泵输出流量以及获得连续出流能力,设计了一种基于合成射流原理的无阀气体压电泵。首先,分析了压电气泵的工作原理,测试了压电振子的振幅;其次,利用CFX软件对无阀气泵进行仿真分析,得到压电气泵在0T,1/4T,2/4T和3/4T时刻的气体流速分布,以及容腔高度、泵腔高度、射流孔直径和出口直径对气泵流量的影响规律;最后,制作了无阀气体压电泵的实验样机。测试结果表明,当无阀压电气泵在驱动电压为120V、驱动频率为400Hz、容腔高度为0.1mm、泵腔高度为1.4mm、射流孔直径为1.3mm和出口直径为2mm时,泵输出气体流量为1800ml/min左右,实验与仿真分析基本吻合。该气泵能输出较大气体流量并具有连续出流的能力。     

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。     

非对称群峰无阀压电泵的结构设计

介绍一种新型的利用非对称群峰嵌入结构形成的无阀压电泵。     

半球缺阻流体无阀压电泵的实验验证

设计了一套压电双晶片作为激励源的半球缺阻流体无阀压电泵。分析了该压电泵的结构及工作原理,并采用有限元软件对其内部流场进行模拟分析。仿真结果表明:该泵存在正反向流阻不等特性,半球缺阻可以作为泵的无运动部件阀。最后,实际制作了半球缺无阀压电样泵和多组半径不等的半球缺,并进行了泵的流阻及流量实验。实验结果表明:该泵正反向流时间差随入口压强增大而减小;当驱动电压为150V,频率为17Hz,半球缺半径为4.0mm时,泵的输出流量达到最大,其值为121.4ml/min;同时,该泵单位时间内的输出流量随半球缺半径增大而呈递减的变化趋势,而且半球缺的半径大小对该类无阀压电泵的工作效能有较大的影响。     

圆弧形流管无阀压电泵的工作原理及试验

圆弧形管路中的液体在压电元件的作用下产生流动,受到离心力和哥氏力的作用。利用上述现象提出了圆弧形流管无阀压电泵,通过压电元件的逆压电效应使泵腔容积产生周期性变化,利用地球自转对流管中流体的影响,使流体顺时针和逆时针两种流动状态的流阻不同,形成流体宏观单向流动。对原理样机进行的压差试验表明:驱动电压保持为130V不变,当驱动频率为14Hz时,压差达到最大值为17mm水柱;当驱动频率为30 Hz时,压差降至3mm水柱。压差的产生源于地球自转的哥氏力,流量或压差的大小能够反映泵结构整体的旋转速度,可望通过地球转速的测量,获得本地地理位置信息,形成导航新原理。     

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。     

非对称群峰结构无阀压电泵的理论分析

提出了一种新颖的非对称群峰结构无阀压电泵.利用泵底的空间,沿泵的出入口轴线方向开发出非对称群峰结构,从而在泵腔内部形成串联的渐扩/渐缩流道,替代了传统的安装在泵腔外的渐扩/渐缩流管.当泵工作时,非对称群峰结构能驱使流体向单一方向流动.建立了数学模型以表达该泵的平均能量损失与流量之间的关系,并分析了该泵的工作原理.实验验证了理论分析的正确性,当一个坡面角固定为90°,而另一坡面角在10°～60°之间变化时,实验数据与理论计算的误差<10%.     

类鹅卵石表面结构阻流体无阀压电泵的试验

鹅卵石表面结构能促进液体流动,为此设计了一种类鹅卵石表面结构阻流体无阀压电泵,建立了其输出流量与流阻比的关系。仿真分析了该泵的泵腔流速分布,对比了其与半球缺阻流体无阀压电泵的流阻比,进行了两种泵样机的流量和压力差试验。结果表明：类鹅卵石表面结构阻流体无阀压电泵的流阻比大于半球缺阻流体无阀压电泵;在220 V驱动电压下,类鹅卵石表面结构阻流体无阀压电泵的最大输出流量和压力差分别为24.98 ml/min和32.5 mm,均优于半球缺阻流体无阀压电泵。     

螺线形流管无阀压电泵的试验研究

流体在螺线形流管中流动时受到的哥氏力,能够增强流体的传质效果,实现输送流体的功能。研究表明进出流管一侧为斜线另一侧为螺旋线的单螺线形流管无阀泵具有泵功能,而进出流管形状为异向螺线时相较于单螺线形流管哪种泵输出性能更优,以及进出流管形状为同向螺线形时是否具有"泵"功能,或者其输出是否低于异向螺线形流管无阀泵,却没有相关研究。为了更好地发挥螺线形流管在无阀压电泵中的优势,拓展该种类无阀泵的应用场合,需要进一步探讨螺线形流管的布局方式对泵输出性能的影响。分析流体在螺线形流管内部的流动情况,推导顺、逆时针流动时的速度差公式,认为螺线形流管无阀泵流量是由进、出水流管的流阻差造成的。利用3D打印技术,设计制作同向螺线、异向螺线以及单螺线形流管三种不同流管布局的无阀压电泵,测量不同频率下三种泵的流量。发现相同电压下,单螺线形流管无阀泵的流量最大,且其最佳工作频率也最大;同向螺线形流管无阀泵也有泵输出,但是输出量很小;当螺线形流管无阀泵的驱动功率较小,其驱动力不足以抵抗流管沿程的流阻损失时,反而体现不出其螺线形流管的优势。     

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)     

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.     

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.     

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.     

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。     

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。     

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.     

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.     

Theoretical analysis and experimental investigation of valveless piezoelectric pump with unsymmetrical ridges

A novel valveless piezoelectric pump with unsymmetrical ridges is presented at first. It ingeniously utilizes the inner space of its chamber by developing its chamber bottom into unsymmetrical ridges along the direction of the inlet and outlet of the pump. Hence, a series of cuneiform channels are asymmetrically and alternately formed between the unsymmetrical ridges and the piezoelectric vibrator, which enables the pump to form a one-way flow instead of the function of the traditional diffuse or nozzle elements fitted outside the chamber. Then, by analyzing the vibration of the piezoelectric vibrator, the vibration deformation function and the equation of volume change are established. Meanwhile, the theoretical equation of the pump flow rate is established. Finally, a real valveless piezoelectric pump with unsymmetrical ridges is manufactured, and the flow rate of the pump is measured through experiments. It is proved that the theory is rational and correct by comparing the experimental flow rate and the theoretical flow rate. In addition, for calculating the theoretical flow rate, the positive and converse flow resistance coefficients of unsymmetrical ridges are measured through experiments, when one slope angle of the unsymmetrical ridges is 90° and another is changing from 20° to 60°, respectively.