Two dimensional polar micro-pumping of fluids using MEMS electrode arrays

The purpose of this thesis is to explore, using CFD simulation and experimental observation, circular fluid flow generated by MEMS electrode arrays underwater.; The fluid flow examined in this thesis was generated by a process called traveling wave AC electro-osmosis. This phenomenon uses multi-phase non-uniform electric fields, generated in the fluid medium, to produce net motion of the fluid. The theory behind traveling wave AC electro-osmosis is explored through simulation and comparisons are drawn between linear and circular arrays. Traveling wave AC electro-osmosis as a means of moving particles in two polar dimensions, theta and r, is demonstrated. It is observed that initially particles circle rapidly above the array and move slowly radially to finally form a thin ring at an equilibrium radius. A theoretical explanation is offered for this observation.; Three-dimensional CFD simulations are performed and cross-sectional information is extracted to obtain tangential (Utheta) velocity as a function of r. Orbital velocity and equilibrium radius measurements are performed at various voltages. Velocities and radii are found to be in general agreement with the simulated results. CFD simulations of future rotational chip designs are also presented, along with a brief explanation of their potential applications.