Highly efficient passive Tesla valves for microfluidic applications  

作　　者：Sebastian Bohm Hai Binh Phi Ayaka Moriyama Erich Runge Steffen Strehle Jörg König Christian Cierpka Lars Dittrich 

机构地区：[1]Theoretical Physics I,Technische Universität Ilmenau,Weimarer Straße 25,98693 Ilmenau,Germany [2]Research and Development,5microns GmbH,Margarethenstraße 6,98693 Ilmenau,Germany [3]Institute of Micro-and Nanotechnologies,Gustav-Kirchhoff-Straße 7,98693 Ilmenau,Germany [4]Microsystems Engineering,Technische Universität Ilmenau,Max-Planck-Ring 12,98693 Ilmenau,Germany [5]Physics and Astronomy,Carleton College,One North College,Northfield 55057 Minnesota,USA [6]Engineering Thermodynamics,Technische Universität Ilmenau,Am Helmholtzring 1,98693 Ilmenau,Germany

出　　处：《Microsystems & Nanoengineering》2022年第5期125-136,共12页微系统与纳米工程（英文）

基　　金：the research project within the framework of the Zentrales Innovationsprogramm Mittelstand(ZIM,funding number:ZF4457306PO9).

摘　　要：A multistage optimization method is developed yielding Tesla valves that are efficient even at low flow rates,characteristic,e.g.,for almost all microfluidic systems,where passive valves have intrinsic advantages over active ones.We report on optimized structures that show a diodicity of up to 1.8 already at flow rates of 20μl s^(−1) corresponding to a Reynolds number of 36.Centerpiece of the design is a topological optimization based on the finite element method.It is set-up to yield easy-to-fabricate valve structures with a small footprint that can be directly used in microfluidic systems.Our numerical two-dimensional optimization takes into account the finite height of the channel approximately by means of a so-called shallow-channel approximation.Based on the threedimensionally extruded optimized designs,various test structures were fabricated using standard,widely available microsystem manufacturing techniques.The manufacturing process is described in detail since it can be used for the production of similar cost-effective microfluidic systems.For the experimentally fabricated chips,the efficiency of the different valve designs,i.e.,the diodicity defined as the ratio of the measured pressure drops in backward and forward flow directions,respectively,is measured and compared to theoretical predictions obtained from full 3D calculations of the Tesla valves.Good agreement is found.In addition to the direct measurement of the diodicities,the flow profiles in the fabricated test structures are determined using a two-dimensional microscopic particle image velocimetry(μPIV)method.Again,a reasonable good agreement of the measured flow profiles with simulated predictions is observed.

关 键 词：BACKWARD HIGHLY optimization 

分 类 号：TN492[电子电信—微电子学与固体电子学]