1 DPD Simulation of Electroosmotic Flow in Nanochannels and the Evaluation of Effective Parameters Masoud Darbandi 1 , Ramin Zakeri 2 Sharif University of Technology, Tehran, P.O. Box 11365-8639, Iran Gerry E. Schneider 3 University of Waterloo, Waterloo, Ontario, N2L 3G1, Canada We provide the simulation of electroosmotic phenomenon in nanochannels using the Dissipative Particle Dynamics (DPD) method. We study the electroosmotic phenomenon for both newtonian and non-newtonian fluids. Literature shows that most of past electroosmotic studies have been concentrated on continuum newtonian fluids. However, there are many nano/microfluidic applications, which need to be treated as either non- newtonian fluids or non-continuum fluids. In this paper, we simulate the electroosmotic flow in nanochannel considering no limit if it is neither continuum nor non-nonewtonian. As is known, the DPD method has several important advantages compared with the classical molecular dynamics (MD) method, e.g., it is computationally more affordable. We benefit from the advantages of DPD method and expand our study to explore the effect of fluid and nanochannel parameters on the electroosmotic flow performance. In other words, we study the parameters that affect the rate of electroosmotic flow and demonstrate the complex behavior of the achieved velocity profiles for newtonian and different types of non-newtonian fluids under various fluid and nanochannel conditions. I. Introduction There are many types of fluid flow in nanochannels performing different flow characteristics, of which the electroosmotic flow (EOF) is an important one. EOF has numerous applications in Micro-Electro-Mechanical Systems (MEMS) and Nano-Electro-Mechanical Systems (NEMS). One important application is to pump fluids in nanoscale. Generally, electroosmosis describes the bulk motion of a liquid in the vicinity of a charged solid surface and in response to an electric field applied parallel to the surface. Indeed, EOF offers many advantages over the conventional pressure-driven flow in that no moving parts are required and the plug-like velocity profile reduces the dispersion of discrete samples. Along these capablities, it provides the ease of fabrication, a higher reliability, less noise, and enhanced controllability. It is also well suited to be miniaturized. The microfabricated fluidic devices have already experienced many EOF applications. They have been extensively used in pumping fluids through either a capillary [1] or a channel micromachined in a chip during electrophoresis [2], liquid chromatographic separations [3], drug delivery devices [4], flow injection analyses [5], micromechanical actuators [6], cooling of microelectronics [7], water management in fuel cells [8], and fuel injection in nanosatellites [9]. Literature shows that the simulation of EOF in nano/microscale is very important for efficient control and optimal design of such devices [10]. Smoluchowski [11] presented an analytical solution for the EOF in a simple channel. Apart from the analytical investigations, the numerical simulations of EOF in the complex geometries of microchannel networks have been pursued by many researchers, e.g. Bianchi, et al. [12], Patankar, and Hu [13], Ermakov, et al. [14], and Darbandi, et al. [15]. However, the coupling of the Navier-Stokes and Poisson-Boltzmann equations under the two assumptions of continuum and newtonian fluid in nanoscale does not necessarily describe the real phenomenon that occurs in many EOF cases. Indeed, there have been some efforts to model the non-continuum electroosmotic flow in past 1 Professor, Center of Excellence in Aerospace Systems, Department of Aerospace Engineering 2 Graduate Student, Department of Aerospace Engineering. 3 Professor, Department of Mechanical and Mechatronics Engineering, AIAA Fellow 10th AIAA/ASME Joint Thermophysics and Heat Transfer Conference 28 June - 1 July 2010, Chicago, Illinois AIAA 2010-5058 Copyright © 2010 by Masoud Darbandi. Published by the American Institute of Aeronautics and Astronautics, Inc., with permission.