Thermal Effects on Electro-Osmotic Flows in Triangle Microchannels

Small triangle channels are frequently encountered in microelectromechanical systems (MEMS). In this paper, the electro-osmotic flows with a constant wall temperature in triangle microchannels are studied. We numerically solved the Poisson equation for electric potential, the Navier-Stokes equation, and the energy equation for the mixed electroosmotic/pressure driven flows with varying physical properties in triangle microchannels using the Galerkin method. The effects of the pressure gradient, the length ratio, κD_h, and Joule heating on mass flux of electro-osmotic flow are discussed, respectively. The numerical results show the mass-flux increases with the increase of imposed positive pressure gradient. A larger Joule number leads to a larger mass flux of electrolytic solution under positive pressure gradient. It is also found that the mass flux increases with increasing the length ratio, κD_h, at a given pressure gradient. The increase in Ju number induces a larger increase in the mass flux at a larger κD_h.