微尺度下粘弹性介电液体的电水动力学传导泵

Electrohydrodynamic conduction pumping of viscoelastic dielectric liquids on the microscale

电流体动力学传导泵送技术可应用于许多高电场强度状态(10^(6)V/m)下工作的宏观设备.随着热管理设备的广泛开发,微尺度流动生成变得越来越重要.这些设备目前用于冷却小表面面积的高热量流源,并可以在各种电子、控制热传递和航空航天场景中找到.此外,微泵中施加电压的幅度可以显著降低,从而节省能源并实现可靠的流动生成。在本研究中,我们探究了嵌入矩形微通道中传导微泵的动态特性,研究了库仑驱动力、不同通道高度、聚合物弹性和粘度比的影响.结果显示,随着通道高度的增加,电力消耗可以变化两个数量级.随着聚合物浓度的增加,最大速度显著减小,并可以达到与未添加聚合物相比的50%,呈柱塞状分布.流量取决于聚合物浓度,但在聚合物弹性下呈现出非线性曲线.这意味着通过调节粘度比来保持微泵的流量性能可控制,可以为某些受控流量应用提供一些建议.

Electrohydrodynamic(EHD)conduction pumping can be applied in many macroscopic devices accompanied by a high electric field intensity(10^(6)V/m).Microscale flow generation has become increasingly important with the widespread development of thermal management devices,which are currently used to cool high heat flux sources with small surface areas and are found in a variety of electronic,controlled heat transfer,and aerospace scenarios.Additionally,the magnitude of the applied voltage can be significantly reduced in micropumping,resulting in power savings and a reliable method for flow generation.In this study,we examine the dynamic characteristics of a conduction micropump embedded within a rectangular microchannel,showing the effects of Coulombic driving forces,different channel heights,polymer elasticity,and viscosity ratios.The results show that electric power consumption can vary by two orders of magnitude for increasing channel height.As the polymer concentration increases,the maximum velocity decreases significantly and can reach 50%of that of the unadded polymer with a plunger-like distribution.The flow rate depends linearly on the polymer concentration,but exhibits non-monotonic curve with the polymer elasticity.It means that the flow rate performance of the micro-pump can be kept controllable by tuning the viscosity ratio,providing some suggestions for some regulated flow applications.