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。     

变截面“Y”型流管无阀压电泵原理及试验

根据三通全扩散/收缩流管的结构形式,设计了一种无阀压电泵——变截面“Y”型流管无阀压电泵。首先,分析了变截面 “Y”型流管无阀压电泵的工作原理;然后,对变截面“Y”型流管流阻和泵流量进行理论分析,对变截面“Y”型流管进行模拟,得到流管正反向压强损失系数;最后,制作变截面“Y”型流管无阀压电泵样机,并进行流量试验。试验表明：当驱动电压为100 V、驱动频率为12.4 Hz时,流量达到最大,为25.7 ml/min;使用定频12.4 Hz改变电压,当电压为200 V时,最大流量达到41.6 ml/min。该组试验证明了变截面“Y”型流管无阀压电泵的有效性。     

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。     

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泵进行内部流场动网格仿真,发现内部流场稳定性随着β角的增加而降低,而最佳输出流量伴随着角度的增加而增加,对比相同压差下流线形流管和锥形流管的仿真结果,发现流线形流管可有效提高流体流动的稳定性;最后,对4组不同角度的样泵进行流量测量实验,并将实验结果与仿真结果进行对比。结果表明:实验得到的最佳输出流量变化趋势以及泵送方向均与仿真结果一致。本研究促进了流线形流管无阀压电泵在微活性物输送领域以及医疗保健领域的应用。     

"Y"形流管无阀压电泵模拟与试验

对"Y"形流管无阀压电泵内部流场及泵流量特性进行了模拟及试验研究.采用CFX软件对"Y"形流管无阀压电泵泵腔内的流场特性进行了模拟分析.结果表明:"Y"形流管无阀压电泵工作时泵腔内的压强变化很小,涡旋对流体传输活体细胞及长链大分子基本无影响.实际制作了"Y"形流管无阀压电泵,并通过改变"Y"形流管的几何尺寸,研究了压电泵进出口端压差的变化规律.试验结果表明,压差随支管夹角增大而减小,并且当两支管宽的和接近主管宽时,压差值达到最小,当支管夹角为5°,宽为1.2 mm时,压差达到最大725 Pa.     

细胞或高分子输送用"Y"形流管无阀压电泵的工作原理及流量特性

在泵腔上安装两支互为倒置的具有一定夹角的三通流管,组成泵腔的流入、排出口,并与压电振子、泵体及其他部件共同构成了"Y"形流管无阀压电泵.该泵无自身化学污染源及电磁污染源,也没有阀的开启过程;同时,具有极大的可微小化和集成化的结构能力;而且,在流管内产生的漩涡相对较小,有利于输送活体细胞及长链高分子.提出新型"Y"形流管无阀压电泵的结构.基于有限体积法,分别模拟锥形流管与"Y"形流管中的压力分布与速度矢量分布,证明"Y"形流管中的漩涡远小于圆锥流管中的漩涡,速度、压力的变化也较圆锥流管低.通过具体分析压电振子的振动,建立泵容积变化方程;同时建立泵流量与压电振子频率之间的关系式.最后,通过对所研究的"Y"形流管无阀压电泵进行流量试验后证明"Y"形流管无阀压电泵具有泵特性,进而证明了上述理论模型的正确性.     

"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。     

"Y"形流管无阀压电泵流量及流管流阻特性分析

目前已有无阀压电泵所采用的无移动部件阀要么结构复杂,要么会产生速度、压强变化显著的湍流流场,不利于应用在医疗、卫生、保健等领域进行活体细胞或长链高分子细胞的输送.针对这些问题,研制一种新型无阀压电泵--"Y"形流管无阀压电泵,并对其进行模拟及试验研究.结合医疗领域输血、输液工作的需要,分析当前几种典型无移动部件阀的优缺点,并介绍"Y"形流管无阀压电泵及其流管的特点.对"Y"形流管无阀压电泵进行理论分析,建立泵流量计算公式.基于有限元法对"Y"形流管内流体流动状态进行模拟,得到"Y"形流管内正反流压强变化规律及内部涡旋较锥形流管内涡旋小的结论,并计算得到"Y"形流管正反向流阻.对"Y"形流管无阀压电泵进行理论与试验流量的比较分析,结果表明,理论泵流量与试验泵流量的最小与最大相对误差分别为7%、13%,也证明了理论分析与数值模拟是正确的.     

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。     

“Y”形流管无阀压电泵模拟与试验研究

为了对“Y”形流管无阀压电泵的工作特性有更深入的了解,使其更好地满足输血、输液等工作的需要,对“Y”形流管无阀压电泵内部流场及泵流量特性进行了模拟及试验研究。采用CFX软件对“Y”形流管无阀压电泵泵腔内的流场特性进行了模拟分析。结果表明：“Y”形流管无阀压电泵工作时泵腔内的压强变化很小,涡旋对流体传输活体细胞及长链大分子基本无影响。实际制作了“Y”形流管无阀压电泵,并通过改变“Y”形流管的几何尺寸,研究了压电泵进出口端压差的变化规律。试验结果表明压差随支管夹角增大而减小,并且当两支管宽的和接近主管宽时,压差值达到最小,当支管夹角为5°,宽为1.2mm时,压差达到最大的74mm水柱。     

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.     

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.     

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.     

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。     

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。     

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。