aus der Wiesche S., Rembe C., Maier C., Hofer E.P.
University of Ulm, DE
Keywords: boiling nucleation, bubble dynamics, microfluidic systems, microheaters
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.
Journal: TechConnect Briefs
Volume: Technical Proceedings of the 1999 International Conference on Modeling and Simulation of Microsystems
Published: April 19, 1999
Pages: 510 - 513
Industry sector: Sensors, MEMS, Electronics
Topics: Informatics, Modeling & Simulation, Micro & Bio Fluidics, Lab-on-Chip
ISBN: 0-9666135-4-6