BPCPPDYSOE21 – wissenschaftliches Programm

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DY: Fachverband Dynamik und Statistische Physik

DY 14: Microfluidics and Droplets - organized by Uwe Thiele (Münster)

DY 14.4: Vortrag

Montag, 22. März 2021, 17:00–17:20, DYa

Theoretical and numerical investigation of an EWOD-driven micro pump — •Sebastian Bohm and Erich Runge — Technische Universität Ilmenau, Theoretische Physik 1, Weimarer Straße 25, 98693 Ilmenau

We show how the EWOD (electrowetting-on-dielectric) effect can be used to realize a micro pump that uses no moveable components at all, as described in [1]. The flow is generated due to the periodic movement of liquid-vapor interfaces in a large number (≈ 10⁶) of microcavities (Δ V≈ 1 pl per cavity). The total flow resulting from all microcavities adds up to a few hundred nanolitres per cycle. Tesla-Diodes are used as valves to completely forgo on moving parts.
The theoretical description of the pumping mechanism is a challenge due to the coupling of the fluid- and electrodynamics and the intrinsic multi-scale character of the system. The flow in each microcavity can be modelled as multiphase flow with time-dependent wetting properties as boundary conditions. The optimization of the Tesla diodes is also a challenge, as they must produce a reasonable valve action even at small Reynold numbers, which are typical for microfluidics.
A novel time-efficient simulation method for the calculation of the static interface shapes of a liquid-vapor interface in electric fields is presented. With this method, the voltage-dependent volume stroke can be determined efficiently. Topological optimization methods for the design of the Tesla-Diodes are shown. Finally, possibilities for the time-resolved simulation of the entire pumping system are discussed.
[1] Hoffmann, M., Dittrich, L., Bertko, M.; DE11 2011 104 467 (2012)