MSM 99
MSM 99
Technical Proceedings of the 1999 International Conference on Modeling and Simulation of Microsystems

Computational Methods for Microfluidics Chapter 15

Dynamics in Microfluidic Systems with Microheaters

Authors: S. aus der Wiesche, C. Rembe, C. Maier and E.P. Hofer

Affilation: University of Ulm, Germany

Pages: 510 - 513

Keywords: microfluidic systems, microheaters, boiling nucleation, bubble dynamics

The physics of nucleation, boiling, bubble growth and collapse in thermal microactuators will be presented. The boiling process exhibits an equivalence to a phase transition of second order and this leads, in contrast to classical nucleation theory, to spatial extended nuclei. The dynamics of the resulting bubbles which grow from such extended nuclei is quite different from the dynamics of common vapor bubbles. However, a simple nucleation criterion can be given. The mathematical modeling and simulation of thermal microactuators is studied. The finite-volume-method is used to solve the coupled constitutive equations, i.e. the electrical potential equation for the heater, the nonlinear heat diffusion equation, and the three dimensional Navier-Stokes equation. Due to a hydrodynamic instability, the resulting bubble flow is found to be appreciable different from the corresponding perfect potential flow. The theoretical results agree well with experimental facts.

ISBN: 0-9666135-4-6
Pages: 697