ELECTROFLUIDIC FULL-SYSTEM MODELING OF A FLAP VALVE MICROPUMP BASED ON KIRCHHOFFIAN NETWORK THEORY

We describe a comprehensive methodology for setting up physically base d consistent full-system models for the effort-economizing and yet acc urate numerical simulation of microsystems and we demonstrate its prac ticality with reference to an electrofluidic micropump macromodel. In this approach, the microsystem is partitioned into functional blocks ( lumped elements). which interact with each other as constituent parts of a generalized Kirchhoffian network. For each of them, a compact mod el with only a few degrees of freedom is formulated. This is achieved by using a flux-conserving discretization of the system of balance equ ations which govern the flow of the relevant physical quantities. In t he case of a micropump, these quantities are the flows of volume, char ge and momentum caused by the respective driving forces which, in cont inuum theory, are the gradients of the spatial distributions of pressu re, voltage and velocity. In this sense, generalized Kirchhoffian netw ork theory is the discrete counterpart of continuum transport theory a nd relies on the same basic physical conservation laws as described by the principles of irreversible thermodynamics. An adequate formal rep resentation of the system description is provided by an appropriate an alog hardware description language such as VHDL-AMS, as it allows the models of the individual system components to be coded as well as the full system to be assembled by linking the constituent parts. Again, t he general principles underlying our approach are exemplified by a ful l-system transient analysis of our benchmark problem, the electrostati cally driven micropump. (C) 1998 Elsevier Science S.A. All rights rese rved.